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Digitized  by  the  Internet  Archive 
in  2015 


https://archive.org/details/firstlessonsinmeOOcomp_0 


FIRST  LESSOJStS 


METAL- WORKING. 


BT 

ALFRED  G.  COMPTON, 

PROFESSOR  OF  AP:  LIED  MATHEMATICS  IN  THE  COLLEGE  OF  THE  CITY  OF  NEW  YORK, 
INSTRUCTOR  IN  CHARGE  OF  THE  WORKSHOPS  OF  THE  COLLEGE,  AL'THOR 
OF  "A  MANUAL  OF  LOGARITHMIC  COMPUTATION,"  AND 
OF  "first  LESSONS  IN  WOOD- WORKING." 


NEW  YORK: 
JOHN  WILEY  &  SONS, 
53  East  Tenth  Steeet. 
1890. 


CPA/5 

Vs- 
C66 


Copyright,  1890, 

BY 

JOHN  WILEY  &  SONS. 


Robert  Drummont  .  Ferris  Bros., 

Electrotype)',  Pnnters, 

m        m;  Pcai  l  St.  326  Pearl  Street, 

New  York.  New  York. 


PREFACE. 


The  first  year  of  instruction  in  handicraft^  as 
experience  in  the  College  of  the  City  of  New 
York  has  shown,  may  be  given  to  wood  working 
or  metal-working  with  about  equal  advantage. 
The  minute  accuracy,  the  acquaintance  with 
geometrical  construction,  and  the  habits  of  neat- 
ness and  cleanliness  which  are  essential  in  the 
one  are  offset  by  the  judgment,  forethought,  and 
artistic  freedom  of  the  other.  Both  constantly 
teach  the  lesson  of  orderly  procedure,  careful  at- 
tention to  instructions,  and,  where  a  text-book  is 
used,  of  minute  and  thoughtful  reading,  such  as 
takes  in  the  full  significance  of  every  pi'oposition 
and  every  limitation  of  it.  The  feeling  of  good- 
fellowship  which  results  from  struggling  with  the 
same  difficulties,  and  occasionally,  as  in  wood- 
working, and  still  more  frequently,  as  in  forge- 
work,  lending  a  helping  hand  to  each  other,  is 
a  valuable  part  of  the  product  of  workshop 
training  in  either  department.    It  has  been  the 

iii 


iv 


PREFACE. 


author's  practice  thei'efore,  for  some  time,  to  let  a 
portion  of  each  class  begiu  in  the  wood-working 
shop,  and  another  in  the  forge  and  vise-room.  The 
advantage  is  thus  secured  of  having  both  shops 
well  filled  ;  while  otherwise,  as  the  second  year's 
class  is  always  smaller  than  the  first,  one  shop  is 
overcrowded  at  the  same  time  that  the  other  is 
perhaps  not  more  than  half  full. 

The  amount  of  knowledge  of  drawing  required 
for  these  lessons  is  about  the  same  as  that  given 
in  the  author's  First  Lessons  in  Wood- Working ; 
so  that  if  Metal- Working  is  taken  up  first,  the  stu- 
dent should  be  taught  as  much  of  the  latter  book 
as  is  found  in  Lessons  VI,  VII,  and  XXI. 

Considerable  thought  and  space  have  been 
given  to  the  description  and  orderly  development 
of  the  processes  of  manufacture  of  iron  and  steel, 
and  of  the  annealing,  hardening  and  tempering 
of  the  latter.  The  book  being  intended,  not  for 
those  who  are  merely  acquiring  a  trade,  but  for 
those  who  are  learning  to  think,  and  to  give  clear 
expression  to  their  thought,  the  lessons  on  this 
subject  are  intended  to  be  thoroughly  mastered, 
both  by  study  and  by  practice,  so  that  the  student 
shall  be  able  to  explain,  in  good  language,  the  rea- 
sons of  the  various  processes  he  uses. 


TABLE  OF  CONTENTS. 


PAGE 

Preface  

Lesson  I.  Metal- working  Tools,  Wrought-iron  and  Cast-iron, 

Cutting  and  Breaking   1 

II.  Care  of  Fire,  Drawing  and  Pointing   7 

III.  Bending,  Turning  an  Eye. .  „    13 

IV.  Flattening,  Punching,  and  Bending   18 

V.  Pointing  and  Twisting   22 

VI.  Welding   28 

VII.  Upsetting  and  Welding   84 

VIII.  Blacksmith  and  Helper   45 

IX.  Welding  continued  :  A  Tongue-weld   51 

X.  Testing  Iron,  Manufacture  of  Cast-iron   58 

XI.  Foundry-work   64 

XII.  Manufacture  and  Properties  of  Wrought  iron   71 

XIIL                                            Steel   75 

XIV.  Welding  Steel  :  Low  Grade   81 

XV.       "         "       High  Grade   85 

XVL  Hardening  and  Tempering  Steel   88 

XVIL                   ^'    98 

XVIII.        "         "          "    105 

XIX.  Chipping   114 

XX.  Drilling  and  Sawing   126 

XXI.  Filing   132 

XXII.  Soldering — Bunsen  Burner    148 

XXm.        ' '          Tlie  Soldering-iron   157 

XXIV.        "          Blow-pipe   165 

Alphabetical  Index   169 


FiKST  Lessoists 

IN 

METAL-WORKING. 


LESSON  1. 

METAL-WORKmG  TOOLS.     WKOUGHT-IROI^  AND  CAST- 
IRON^.      CUTTING  AND  BREAKING. 

The  tools  used  in  cutting  iron,  like  those  used 
in  wood- working,  are  wedges.  They  are  thrust 
in  or  driven  in  between  the  particles  of  the  metal, 
separating  them  from  each  other,  making  notches 
in  the  piece,  and,  if  they  penetrate  far  enough, 
tearing  off  chips  or  cutting  the  piece  in  two. 
Metal  being  much  harder  than  wood,  it  is  gener- 
ally necessary  to  drive  the  cutting-tool  forw^ard 
by  blows  of  a  hammer,  as  is  the  case  in  wood- 
working also  when  the  cut  is  deep  or  across  the 
grain  of  the  wood.  When  the  metal  and  the 
tool  can  be  held  in  powerful  machines,  such  as 
the  engine-lathe  and  the  planing-machine,  which 
you  will  understand  by  and  by,  a  steady  push  can 


2  FIBST  LESSONS  IN  METAL-  WORKING. 


be  used,  but  without  these,  blows  of  a  hammer 
are  generally  necessary. 

Again,  metal  being  much  harder  than  wood,  a 
different  form  has  to  be  given  to  the  cutting-tool. 
For  wood-working  the  wedge  may  be  thin,  and 
therefore  can  be  made  to  penetrate  easily.  The 
two  faces  of  a  knife,  hatchet,  or  chisel  make 
witli  each  other  an  angle  of  about  25°,  which  is 
increased  to  35°  near  the  edge,  by  the  sharpening 
of  the  tool  on  the  oil-stone.  Even  this  is  some- 
times found  to  be  too  small,  and  the  tool  splinters 
or  nicks"  when  cutting  hard,  w^ood.  For  iron, 
therefore,  the  angle  must  be  larger  than  this.  It 
need  not  be  much  larger  if  the  tool  is  not  very 
brittle  and  if  it  is  used  only  for  cutting  straight 
forward  ;  but  when  the  metal  of  the  tool  is  very 
hard,  or  when  the  tool  is  strained  crosswise  in 
cutting,  the  angle  must  be  larger,  and  is,  in  some 
lathe-tools,  as  great  as  90°. 

Again,  metals  being  very  hard,  metal-tools  are 
much  heated  if  driven  fast.  It  is  a  familiar  fact 
that  rubbing,  compressing,  or  tearing  asunder 
any  material  produces  heat.  ood  is  heated  by 
repeated  blows  of  a  hammer.  In  boring  holes, 
the  wood  and  the  bit  become  hot.  When  the 
material  worked  is  so  hard  as  iron,  if  tools  are 
pressed  against  it  hard  enough  to  cut  it  and  then 
are  moved  rapidly,  a  great  deal  of  heat  is  pro- 
duced.   In  this  case  the  heat  may  be  enough  to 


METAL-WORKING  TOOLS. 


3 


soften  and  spoil  the  too],  and  it  is  necessary 
therefore  to  work  more  slowly. 

In  metal- woi'king  there  is  no  operation  like  that 
of  splitting  or  hewing :  chipping,  which  comes 
nearest  to  it,  is  considerably  slower.  In  all  metal- 
working,  therefore,  the  pieces  are  fashioned  nearly 
to  the  desired  shape  while  they  are  soft,  and  the 
work  which  the  cntting-tool  has  to  perform  is 
thus  lessened.  There  are  two  ways  in  which  the 
metal  is  thns  prepared — casting  and  forging. 

Casting  is  melting  the  metal  and  pouring  it 
into  moulds  of  the  proper  shape.  In  this  case 
heat  performs  the  greater  part  of  the  work.  It 
separates  the  particles  of  the  metal  from  each 
other  so  that  they  can  flow  into  every  corner  of 
the  mould,  and  the  workman  has  then  only  to 
finish  the  surface  of  the  casting  with  suitable  tools. 

Forging  is  hammering  the  metal  while  it  is 
soft.  All  metals  melt  when  heated.  The  tem- 
perature for  melting  ranges  from  about  450°  F. 
for  tin  to  about  4500°  F.  for  platinum.  Before 
reaching  the  melting-point,  the  metal  becomes 
soft,  and,  while  in  this  state,  if  two  perfectly 
clean  surfaces  are  brought  into  close  contact,  they 
adhere  and  the  two  pieces  become  one.  This 
process  is  Avelding.  While  in  the  soft  state  also, 
a  metal  can  be  hammered  into  almost  any  desired 
shape.  This  process  is  forging.  The  two  pro- 
cesses of  forging  and  welding  are  generally  in- 


4 


FIRST  LESSON'S  IK  METAL-WORKING. 


eluded  under  the  term  ''forge-work"  or  ''forging." 
They  are  applicable,  as  casting  is,  to  various 
metals ;  but  all  three  are  important  chiefly  in 
the  case  of  iron  and  steel,  because  of  the  ease 
with  which  the  operations  can  be  performed, 
and  the  abundance,  cheapness,  and  strength  of 
the  metals. 

The  iron  used  for  casting,  or  foundry- work, 
and  that  used  for  forge- work,  are  called  respect- 
ively cast-iron  and  wrought-iron.  Cast-iron  is 
iron  combined  with  carbon ;  wrought-iron  is  the 
same  metal  after  as  much  as  possible  of  the  car- 
bon is  removed.  We  will  begin  our  exercises  in 
forge-work  by  studying  some  of  the  differences 
between  them. 

Examine  the  two  specimens  of  iron  on  your 
anvil.  Holding  each  loosely  between  the  fingers, 
strike  it  on  the  edge  of  the  anvil.  Observe  the 
ringing  of  the  one  and  the  duller  sound  of  the 
other.  Strike  them  on  the  edge  with  the  edge  of 
your  hammer,  and  observe  the  difference  in  the 
character  of  the  nick.  Lay  them  on  the  anvil, 
and  hammer  them  pretty  vigorously  at  one  end. 
One  flattens,  the  other  does  not ;  one  is  malleable, 
the  other  is  not.  When  you  have  learned  to  use 
the  fire,  repeat  this  last  experiment  while  the 
pieces  are  red-hot,  and  you  will  find  the  difference 
greater  still.  Lay  them  across  two  supports, 
about  3"  apart  on  the  anvil,  as  in  Fig.  1,  and 


METAL-WORKING  TOOLS. 


5 


strike  tliem  with  the  hammer  (being  careful  not 
to  stoop  over  them,  lest  they  fly  up  and  hurt  you). 


Fig.  1. 

One  bends,  the  other  very  probably  breaks.^ 
Next  try  to  break  the  bent  one:  you  find  this 
difiicult.  At  one  end  of  the  anvil  is  a  chisel, 
called  the  ^^hardee"  or  "  hardy,"  mean-  Exercise  i. 
ing  ^'  hard  edge,"  being  made  of  steel.  Cutting  with 
and  hardened  on  the  edge.  Lay  the  i^^rdee. 
unbroken  piece  over  this,  and  strike  it  two  or 
three  times  with  the  hammer,  making  a  nick  in 
it.  Be  very  careful  not  to  strike  the  hardy  with 
the  hammer.  Turn  the  piece  over,  and  nick  the 
other  side,  exactly  opposite  the  first  notch.  When 
you  have  cut  it  thus,  you  w411  find  that  you  can 
break  it  by  laying  it  over  the  two  supports,  and 


*  The  same  experiment  may  be  made  with  less  risk  of  injury  from 
the  flying  fragments  when  the  piece  breaks,  by  holding  each  piece 
in  the  vise  while  striking  the  blow.  Let  it  project  three  or  four 
inches  above  the  vise.  Strike  from  you,  towards  the  wall  behind 
your  bench,  so  that,  if  the  piece  flies  olf,  it  will  hit  no  one.  Or,  still 
more  safely,  the  pieces  may  be  bent  by  holding  them  at  the  ends  in 
a  suitable  clamp,  and  pressing  them  down  at  the  middle  by  a  screw. 


6 


FIRST  LESSONS  IN  METAL-  WORKING. 


striking  it  at  the  nick,  or  even,  if  it  is  notched 
pretty  deeply,  by  laying  it  over  the  edge  of  the 
anvil,  and  striking  it  just  beyond  the  notch,  or 
holding  it  in  the  vise,  just  below  the  notch,  and 
striking  at  the  end.  The  tough  piece  is  wrought- 
iron ;  the  brittle  piece  is  cast-iron.  Make  a  writ- 
ten memorandum  of  all  the  differences  between 
them  that  you  can  discover,  including  the  differ- 
ence between  the  surfaces  of  fracture  examined 
with  a  lens. 


CAEE  OF  FIRE.    DRAWING  AND  POINTING.  7 


LESSON  IL 

CARE  OF  FIRE.     DRAWIISTG  A^^D  POUSTTmG. 

When  an  object  is  made  of  wrought-iron,  it 
must  be  made  as  nearly  as  possible  of  the  right 
shape  at  first,  by  forging,  so  that  it  may  require 
little  or  no  finishing  with  cutting  tools.  Forging, 
or  shaping  with  the  hammer,  includes  a  number  of 
distinct  operations,  called  drawing,  pointing,  up- 
setting, bending,  twisting,  punching,  and  welding. 
In  nearly  all  of  these  the  first  step  is  to  make  the 
metal  red  or  white  hot,  and  in  doing  this  the 
proper  management  of  the  fire  is  of  the  highest 
importance. 

Your  forge  has  a  broad  "hearth,"  on  which 
coal  can  be  heaped  up  over  the  mouth  of  a 
pipe  called  the  tuyere"  (pronounced  twee-er). 
Through  this  tuyere  a  current  of  air  can  be  forced 
from  the  bellows  or  blower.  With  a  moderate 
supply  of  air  the  fire  burns  slowly,  and  produces 
a  temperature  of  about  800°  or  900°  C,  equivalent 
to  about  1500°  CO  1700°  F.  Every  atom  of  oxy- 
gen that  unites  with  an  atom  of  cai-bon  in  the  coal 
produces  a  certain  amount  of  heat ;  hence  the 
more  carbon  and  oxygen  used,  the  more  heat  pro- 
duced.   With  a  good  supply  of  air  you  can  raise 


8 


FIRST  LESSONS  IN  METAL-WORKING. 


your  fire,  and  any  piece  of  iron  in  it,  to  about 
1500°  C.  or  2700°  F.  It  is  possible,  however,  to 
furnish  more  air  than  the  carbon  requires  for  its 
combustion.  The  air  then  only  cools  the  carbon, 
or  tends  to  blow  out  the  fire.  A  lighted  stick 
thrust  into  a  bottle  goes  out  for  lack  of  oxygen. 
A  lighted  match  goes  out  in  a  strong  draught 
because  of  excess  of  air.  Remember  this  in  man- 
aging your  fire. 

To  start  your  fire,  place  a  small  heap  of  shav- 

Exercise  2.  ^^S^  ^^^^  throat  of  the  forge. 
Making  a  Light  it,  and  when  it  is  blazing,  scrape 
a  few  pieces  of  coke  or  coal  over  it, 
choosing  such  as  is  free  from  large  lumps.  As 
these  light,  scrape  on  more,  blowing  gently  with 
the  bellows.  Gradually  cover  completely,  and 
blow  harder.  Sprinkle  with  water  the  coal  round 
the  outside  of  the  fire,  which  will  prevent  the  fire 
from  spreading  too  far,  and  will  also  make  coke 
for  the  next  day.  When  once  started,  the  fire 
can  be  kept  covered  and  burning  slowly  for  a  long 
time,  by  leaving  a  stick  of  hard  wood  in  it,  or  can 
be  blown  up  in  a  few  minutes  to  a  white  heat. 

For  your  first  exercise  in  forging,  cut  off  a  piece 
of      round  iron,  exactly  20''  long.    If  you  fail  to 

Exercise  3.  exactly  right,  make  a  memoran- 

Heating  to  a  dum  of  the  length  in  your  note-book, 
white  heat.  ^-jj  ^^^^  make  a  square  point 

two  inches  long  on  the  end  of  this.    Put  the  end 


CAME  OF  FIRE,    DRAWING  AND  POINTING.  9 


in  the  fire,  covering  it  lightly  with  the  coals.  It 
is  best,  particularly  in  working  such  thin  iron  as 
this,  not  to  bury  it  very  deeply  in  the  fire,  but  to 
keep  it  near  the  surface,  where  it  can  be  watched 
through  the  spaces  between  the  coals,  and  re- 
moved as  soon  as  it  reaches  the  proper  heat.  If 
left  too  long  in  a  very  hot  fire,  and  with  a  plenti- 
ful supply  of  air  from  the  bellows,  the  iron  may 
burn  and  the  piece  be  spoiled;  for  iron  is  combus- 
tible, just  as  wood  and  coal  are,  only  it  requires 
a  higher  temperature  to  burn  it.  With  larger 
pieces,  such  as  you  will  have  in  later  exercises, 
this  accident  is  less  likely  to  happen.  Watching 
your  iron,  you  will  see  the  black  rod  get  gradually 
red  and  then  white,  so  as  to  be  indistinguishable 
in  the  midst  of  the  glowing  fuel.  In  this  condi- 
tion it  will  burn  if  left  too  long.  Remove  it  from 
the  fire  by  the  cool  end,  which  will  be  cool  enough 
if  you  have  not  thrust  it  in  too  far,  or  left  it  too 
long.  It  should  be  white-hot  just  at  the  end,  and 
red  about  two  inches  farther.  As  you  carry  it 
through  the  air,  brilliant  white  sparks  will  shoot 
off  from  it,  if  it  is  at  a  good  Avhite  heat :  these 
are  particles  of  iron  burning.  Lay  it,  Avithout  loss 
of  time,  on  the  anvil,  so  that  the  hot  end  rests  on 
the  farther  edge,  the  end  in  your  Exercise  4. 
hand  being  raised  three  or  four  inches.  Drawing  and 
so  that  the  bar  is  inclined  to  the  face  P^i^^^^^- 
of  the  anvil.    Hold  the  hammer  with  its  face 


10  FIRST  LESSONS  IN  METAL-  WORKING. 


similarly  inclined.  Grasp  it  firmly,  with  the 
fingers  under  the  handle  and  the  thumb  ex- 
tending along  the  top.  Then,  with  quick 
light  strokes,  not  near  the  end,  but  at  the 
very  tip,  beat  the  iron  out,  turning  it  to  and  fro 
through  a  quarter  turn  after  each  blow  or  two,  so 
as  not  to  flatten  it,  but  to  make  the  end  square 
and  pointed.  When  a  little  of  the  end  is 
pointed,  you  may  gradually  work  farther  back, 
till  you  have  produced  a  square  point  two  inches 
long.  Be  careful  not  to  continue  hammering, 
particularly  at  the  point,  after  the  iron  has 
lost  its  bright  white  heat.  If  you  do  this  you 
will  probably  split  it.  Wrought-iron,  as  we 
shall  see  later,  is  fibrous  in  structure,  and  the 
fibres,  like  those  of  wood,  can  be  torn  asunder 
more  easily  than  they  can  be  broken  across.  This 
splitting  is  especially  liable  to  happen  in  inferior 
iron.  Just  as  it  does  in  wood  that  is  wanting  in 
toughness,  and  affords  one  means  of  Judging  of 
the  quality  of  the  iron.  If  your  rod  does  split  at 
the  end,  you  can  generally  get  the  parts  to  re- 
unite, by  raising  it  again  to  a  white  heat,  and 
hammering  gently.  This  operation  is  assisted  by 
sprinkling  the  piece  with  white  sand  when  you 
take  it  from  the  fire,  and  putting  it  back  in  the 
fire  a  few  minutes  before  hammering  it.  If  you 
do  not  succeed  in  closing  the  split,  you  must  cut 
off  the  cracked  end  on  your  hardy  and  begin 


CARE  OF  FIRE.    DRAWING  AND  POINTING.  11 


again,  being  more  cai'eful  now  to  keep  the  metal 
at  a  bright  red  heat  when  hammering  near  the 
end,  reheating  it  for  this  purpose  several  times  if 
necessary. 

In  turning  the  piece  to  and  fro  while  hammer- 
ing, you  must  be  careful  to  give  it  Just  a  quarter 
of  a  turn  each  time  ;  otherwise  you  will  give  it  the 


Fig.  2. 


cross-section      Fig.  2,  instead  of  h.    In  this  case 
you  will  have  considerable  trouble  to  restore  the 
proper  shape  by  holding  it  on  the  anvil  as  at 
and  striking  it  at  d. 

When  you  have  pointed  the  piece  and  cooled 
it,  measure  its  length,  and  compare  it  with  the 
length  it  had  at  first.  The  lengthening  of  a  piece 
by  hammering  is  called  di'awing.  Observe  how 
much  you  have  drawn  this,  making  allowance  for 
any  that  you  may  have  cut  off  because  of  splitting. 
It  is  important  that  you  should  learn  to  estimate 
the  amount  of  drawing  in  any  particular  case  in 
order  to  be  able  to  make  allowance  for  it  in  future 
work.  Of  course  this  lengthening  cannot  be  ac- 
complished without  reducing  the  diameter,  either, 
as  in  this  case,  at  the  point,  or  at  some  other  place, 


12 


FIRST  LESSONS  IN  METAL-  WORKING, 


or  along  its  whole  length.  This  last  is  what  takes 
place  in  making  bar-iron."  A  short  thick  mass 
of  iron  is  passed,  while  white-hot,  between  strong 
rollers  such  as  are  shown  in  Fig.  52.  As  the  iron 
passes  through  the  successive  grooves,  it  is  reduced 
in  thickness  and  increased  in  length,  and  comes 
out  at  last  as  bar-iron,  of  the  same  size  and  shape 
as  the  last  groove. 


BENDING,    TUBNING  AN  EYE. 


13 


LESSON  III. 

BENDIISTG.     TURNIlSrG  EYE. 

HAvma  drawn  and  pointed  the  rod,  form  an  eye 
on  it,  as  in  Fig.  3.  The  eye,  being  1''  in  diameter, 
will  be  nearly       in  circumference. 


Fig.  3. 

Heat  about  3  of  the  end  of  the  rod  to  a  bright 
red  heat.  Lay  it  over  the  edge  of  the  anvil,  with 
one  of  the  flat  faces  of  the  point  turned  up,  and 
bend  it  down  at  right-angles  with  a  few  gentle 
blows  of  the  hammer. 

Strike  at  a  and  Z>,  Fig.  4,  alternately,  striking 


a 


Fig.  4. 


from  you  as  well  as  downward,  so  as  to  give  a 
kind  of  pushing  blow,  till  you  have  a  good  square 
bend.  Do  not  hit  with  the  edge  of  the  hammer, 
nor  hard  {enough  to  bruise  the  iron. 


14 


FIRST  LESSONS  IN  METAL-  WORKING. 


Next  place  the  part  h  on  the  "  horn/'  or  round 
end  of  the  anvil,  as  in  Fig.  5,  and  bend  it  round 
as  at  G  and  nearly  closing  the  ring.  Then, 
laying  the  part  bo  on  the  edge  of  the  anvil,  the 


d 

Fig.  5. 


point  d  being  upward,  and  striking  lightly  at  J, 
close  it.  Be  careful  to  make  the  ring  as  nearly 
Exercise  5,  as  possiblc  circular,  perfectly  closed. 
Bending.  .^^idi  Symmetrical  on  the  stem,  as  at 
Fig,  6,  not  one-sided,  as  at  g.  The  last  part  of 
the  eye,  near  the  point  of  closing,  must  be  bent 
with  the  tail  or  "  pene''  of  the  hammer.  If  you 
do  not  succeed  the  first  time,  heat  the  eye  again, 
spread  it  out  by  driving  it  on  the  horn  of  the 
anvil,  and  repeat. 

Jf  the  eye  closes  too  far  down  on  the  stem,  as  at 


BENDING.    TURNING  AN  EYE, 


15 


Fig.  7,  open  it  on  the  horn,  and  then  bend  it  to 
the  proper  shape  with  light  blows  of  the  tail  of 
the  hammer  at  while  resting  on  the  horn  at  c. 
If  it  closes  too  far  up,  as  at  4  strike  at  while 
resting  on  the  horn  at  e.  If  the  iron  gets  too 
much  burned,  you  must  cut  it  off  on  the  hardy 


Fig.  6.  Fig.  7. 


and  begin  again ;  but  this  ought  not  to  occur,  as 
it  spoils  the  proportions  of  the  piece. 

Use  the  eye  already  formed,  if  it  is  a  good  one,  cut- 
ting olf  the  square  point  on  the  hardy.  Exercise  6. 
If  it  is  not  good,  cut  off  another  piece  of  a  forge- 
bar-iron  of  the  proper  length,  and  form  a  P^^®^- 
new  eye.    Flatten  the  rod  for  about  4''  from  the 
end,  to  a  width  of  about  f which        giv  e  a  thick- 
ness of  about         In  flattening,  or  in  any  operation 
in  which  much  hammering  is  to  be  done  on  one  piece, 
do  not  move  the  hammer  about  on  the  anvil,  but 
let  it  fall  constantly  on  the  same  point,  about  the 
middle  of  the  face  of  the  anvil,  and  move  the  iron 


16  FIBST  LESSONS  IN  MEJ AL-WORKING. 

instead  of  the  hammer.  This  principle  is  even  more 
important  when  two  persons  work  on  the  same 
piece,  as  in  some  later  exercises.  Hold  the  rod  so 
that  the  plane  of  the  flattened  portion  shall  be 
perpendicular  to  the  plane  of  the  eye.  In  this, 
as  in  Exercise  4,  page  10,  begin  hammering  at  the 
tip,  and  with  a  good  bright  w^hite  heat,  so  as  not 
to  split  the  rod.  Having  flattened  it  to  the 
proper  amount,  hammer  it  cold,  to  smooth  it. 
Heat  it  again,  lay  it  over  the  edge  of  the  anvil  and 
bend  it  at  right  angles  at     Fig.  8,  as  in  Exercise 

Fig.  8. 

5,  Fig.  4.  Lay  it  across  the  horn  and  bend  the 
curved  part  ha.  Again  lay  it  on  the  edge  of  the 
anvil  as  at  Fig.  9,  and  form  the  straight  end  as 
at  d.  The  plane  of  the  bend  should  be  the  same 
as  the  plane  of  the  eye.  Look  along  the  rod  and 
test  this.  See  also  whether  the  rod  is  straight, 
and  whether  the  plane  of  the  shoi't  flattened  piece 
at  the  end  is  perpendicular  to  the  plane  of  the 
bend  and  the  eye.    Correct  any  crookedness  by 


BENDING.    TURNING  AN  EYE, 


17 


gentle  blows  while  the  iron  is  cooling.  If  the 
plane  of  the  flattened  portion  is  not  perpendicular 
to  the  plane  of  the  ring  and  of  the  curve  ah^  heat 
the  straight  part  near  ah  to  redness,  place  it  on 


Fig.  9. 


the  anvil  so  that  the  eye  is  perpendicular  to  the 
face  of  the  anvil,  and  strike  a  light  blow  or  two  at 
b.  Or  hold  the  ring  in  the  vise,  and,  taking  hold 
with  the  tongs  at  twist  the  i*od  to  the  proper 
position. 


18 


FIBST  LESSONS  IN  METAL- WOUKINQ, 


LESSON  IV. 

FLATTEOTlN^a,  PUNCHmG^  AND  BENDIJSTa. 

While  iron  is  soft  it  is  easy  to  make  holes  in  it 
of  any  desired  shape,  with  a  steel  punch. 

We  will  make  an  ''angle-iron"  or  "bracket," 
Fig.  10,  from  a  piece  of  ^'  round  iron  8''  long. 

p  .  This  is  to  be  first  ham- 

!        ®  ®        I  mered  out  flat  to  a  width 

  ^        . .        ^  of       secondly,  bent  at 

I        ^  ]'ight  angles ;  and,  third- 

ly, punched  with  four 
''-  holes  for  screws.  Take 

a  pie(^e  of  iron  16  long. 
For  the  first  operation, 
heat  one  end  of  the 
piece  to  whiteness,  and, 
J  beginning  as  in  Exercise 

4,  page  10,  at  the  end, 
and  with  the  same  care  to  prevent  splitting,  hammer 
it  down  to  tlje  thickness  of  about  \" ,  Then,  work- 
ing from  the  end  towards  tlie  middle,  flatten  about 
4''  of  the  piece,  working  always  on  the  centre  of 


FLATTENING,  PUNCHING,  AND  BENDING.  19 


the  anvil,  as  in  Ex.  6.  Be  careful  not  to  hammer 
more  on  one  edge  than  on  the  other.  If  you  do 
you  will  bend  the  piece.  If,  for  instance,  you 
hammer  too  much  on  the  right-hand  edge,  you 
will  make  this  edge  not  only  thinner,  but  longer 
than  the  othe]*,  and  will  thus  make  the  piece  bend 
towards  the  left.  If  you  find  this  happening,  you 
can  correct  it  by  hammering  a  little  more  all  along 
the  left-hand  edge,  or  wherever  you  find  it  thicker 
than  elsewhere.  Turn  the  piece  over  occasionally, 
and  hammer  on  the  other  side  to  prevent  the  end 
from  turning  up.  Heat  about  four  inches  more 
of  the  bar,  and  flatten  in  the  same  way  the  rest 
of  the  8'^  that  will  be  required.  Do  not  extend 
the  flattening  more  than  about  a  quarter  of  an 
inch  beyond  the  required  distance.  The  remain- 
der of  the  metal  was  only  left  as  a  handle  to  hold 
the  piece  by,  and  when  you  have  finished,  is  to  be 
cut  off  and  left  undefaced  for  future  use. 

The  piece  is  now  of  the  uniform  width  of 
straight  and  uniformly  thick,  and  is  ready  for 
bending  and  punching.  Before  bending,  bevel 
the  edges  slightly  on  the  side  where  the  heads  of 
the  screws  will  be,  by  hammering,  cold,  on  the 
anvil.  Mark  with  a  centre-punch.  Fig.  11,  b,  the 
place  at  which  the  bend  is  to  be  made.  Heat  the 
piece  to  a  red  heat  at  this  place,  lay  it  on  the  an- 
vil with  the  mark  exactly  over  the  edge,  and, 
while  an  assistant  holds  a  hammer  on  the  piece 


20 


FIRST  LESSONS  IN  METAL-  WORKING. 


Just  behind  the  mark,  bend  it  at  right  angles. 
Or,  liohl  it  in  the  vise  at  the  mark  and  bend  it. 

For  punching,  use  a  slightly  tapering  punch, 
Fig.  11,  A,  about  jig''  in  diameter  at  the  point, 
and  not  more  than        at  one  inch  from  the 
end.    Havino;  marked  with  a  centre- 
Exercise  7.     punch  the  placcs  where  the  holes 

Punching.  ^ 

are  to  be  made,  lay  the  piece,  heated 
to  a  bright  red,  on  the  anvil,  and  drive  the  punch 
half-way  through.    The  piece,  when  turned  over, 


Fig.  11. 

will  show  a  dark  spot  due  to  the  cooling  effect  of 
the  punch.  Apply  the  punch  here  and  drive  it 
through  from  the  other  side,  pushing  out  the 
small  piece  or  burr  by  driving  it  into  one  of  the 
holes  in  the  anvil.  Be  careful  not  to  drive  your 
punch  in  too  far,  or  you  will  spread  the  hole  too 
wide,  and  may  split  the  piece.  Diive  it  so  far  as 
to  enlarge  the  hole  enough  for  the  admission  of 
the  screws  that  are  to  be  used  in  putting  up  the 
bracket.  If  these  are  ^'round-headed"  sci'ews, 
Fig.  12,  A,  this  is  all  that  it  is  necessary,  except  to 
smooth  and  straighten  the  piece  where  it  may 
have  been  bent.  If  they  are  flat-headed,"  Fig. 
12^  B,  the  holes  must  be    counter  sunk,"  that  is, 


FLATTENING,  PUNOHING,  AND  BENDING.  21 


enlarged  at  the  top^  as  in  Fig.  18,  to  coiTespond 
with  the  head  of  the  screw,  and  let  it  come  even 

or      flush  "     Avith  the  surface    of   the    Exercise  8 

iron.    When  only  a  shallow  counter-  Countersink- 
sink  is  required,  it  may  be  made  with 
a  countersink-punch,  Fig.  14,  a  ;  but  to  cut  deep 

V7 


1- 


Fig.  12. 


Fig.  13. 


enough  to  let  the  head  of  a  screw  come  even  with 
the  surface  of  the  iron,  a  countersink-bit.  Fig.  14, 
B,  must  be  used,  as  in  wood-working. 

When  you  have  made  and  countersunk  the 
holes,  finisli  the  piece  as  straight  and  smooth  as 
you  can,  cold.    Finally,  cut  it  off 


at  the  proper  point,  and  bevel  the  F 
newly  cut  edge  like  the  others. 
When  finished,  the  bracket  should 
be  true  to  the  proposed  dimensions, 
exactly  idght-angled  and  free  from 
"winding,"  smooth  and  without 
marks  of  burning,  square  at  the 
ends  and  equally  bevelled  all 
round,  and  the  centres  of  the 
holes  should  be  in  a  line  exactly  parallel  to  the 
edges. 


A 


Fig.  14. 


22 


FIRST  LESSONS  IN  METAL-  WORKING. 


LESSON  Y. 

BENDIIS^G,  POINTmG,  AND  TWISTIl^TG. 

REMEMBERmo  how  much  the  iron  was  drawn  in 
Exercise  4^  provide  a  piece  of  round  iron  of  the 
proper  length  for  the  exercise  shown  in  Fig.  15. 


(FuUSize) 


Fig.  15. 


Keep  a  memorandum  of  the  length  provided^  and 
test  the  correctness  of  your  estimate  by  compari- 
son with  your  finished  work  at  the  end  of  the 
exercise. 

The  iron  in  this  exercise  being  shorty  wnll  have 
to  be  held  with  the  tongs.    Point  both  ends  of 


BENDING,  POINTING,  AND  TWISTING. 


23 


the  piece^  as  in  Exercise  4,  with  the  precautions 
there  indicated.    Make  the  flat  snr- 

Exercise  9. 

iac(  >  at  the  two  ends  to  match.    Heat  a  staple, 
the  piece  at  the  middle  and  bend  it        of  the 
over  the  horn  of  the  anvil.  Attend 
to  the  following  points : 

1.  Hold  the  tongs  so  that  the  opening  between 
the  Jaws  shall  be  horizontal.  One  of  the  jaws 
will  then  be  over  the  piece  you  are  holdings  which 
will  then  not  be  so  easily  knocked  out  of  the 
tongs  as  if  the  opening  were  vertical. 

2.  Let  the  bend  be  in  the  plane  of  two  of  the 
squared  faces. 

3.  Make  the  bend  as  nearly  as  possible  in  the 
middle. 

In  making  the  bend  you  will  probably  bring 
the  points  too  near  together;  in  fact  they  may 
almost  meet.    To  separate  them,  drive  the  staple 


Fig.  16. 


downi  onthehardee,  so  that  the  latter  shall  spread 
out  the  legs.  If  they  are  not  quite  equal,  make 
them  so  by  striking  gently  on  the  curve  while 
holding  the  staple  upright  with  the  point  of  the 
long  leg  resting  on  the  anvil.    Straighten  the 


24  FIRST  LESSONS  IN  METAL-WORKING 


legs  by  thrusting  the  tliin  end  of  the  anvil  be- 
tween  them  as  in  Fig.  16,  and  hammering  lightly 
first  one  and  then  the  other.  Lay  the  staple  on 
the  anvil  and  see  that  the  legs  lie  in  the  same 
plane,  both  touching  the  face  of  the  anvil  in  their 
whole  length.  If  they  do  not,  hold  one  end  in 
the  tongs  and  strike  the  other  near  the  top  or 
circular  end  till  you  correct  the  winding  or  twist ; 
or  you  may  hold  one  end  in  the  vise  and  bend  the 
other  to  the  proper  position  with  the  tongs,  or, 
when  cold,  with  the  fingers.  Examine  the  curve 
carefully  for  any  lack  of  symmetry,  and  correct  it 
by  gentle  blows  over  the  horn  of  the  anvil. 
Finish  it  smooth  when  cold.  Do  not  neglect  to 
compare  your  finished  work  with  your  estimate, 
so  as  to  learn  how  much  to  allow  for  such  objects 
in  the  future. 

Each  ring  in  this  exercise  being  1^^^  in  diame- 
tei*,  the  circumference  will  be  3^  times 
Exercise  10.    ji//       ^^^^^  4//  ^^^^^  together 

An  S-hook.         ,    '        „      .  •         p  i     °  1 

about  8  .  A  portion  oi  the  iron,  about 
at  the  middle,  belongs  to  both  rings.  Deduct- 
ing this,  and  about  \"  to  f'^at  each  end  for  draw- 
ing, leaves  about  6^''  as  the  length  of  the  piece 
of  iron  needed  for  the  job.  Holding  the 
piece  with  the  tongs,  point  each  end,  as  in  Ex- 
ercise 4,  but  round  instead  of  square.  It  will  be 
a  useful  exercise,  and  will  assist  you  in  rounding 
the  iron  symmetrically,  to  make  it  first  square, 


BENDim,  POINTING,  AND  TWISTING.  25 


tlien  octagonal,  and  then  round.  Do  not  make 
the  points  too  long.  If  the  taper 
extends  beyond  Fig.  17,  it  will 
weaken  the  hook.  Be  careful  not 
to  burn  the  points.  Finish  them 
smooth,  cold.  Then,  heating  one 
end  to  redness,  lay  it  on  the  horn 
at  the  middle  of  one  half,  or 
a  little  nearer  to  the  middle 
of  the  piece,  as  at  Fig.  18, 
and  turn  it  as  in  Exercise  5.  Having  formed  one 
eye,  heat  the  other  end  and  form  the  other  in  the 


Fig,  18. 


same  way.  The  points  of  the  hook  should  be 
bent  down  almost  to  the  stem,  as  at  c,  Fig.  17, 
leaving  an  opening  of  about 
Both  eyes  should  be  exactly  circu- 
lar and  equal,  the  hook  appearing 
as  in  Fig.  17,  not  as  in  Fig.  19, 
where  ah  is  too  nearly  straight,  and 
the  eyes  are  too  pointed  at  c. 

You  have  now  discovered  that 
forge-work    requires    more  judg- 
ment by  the  eye  than  wood- work. 
It  is  not  possible  to  mark  out  your  work  with 
rule  and  square.    You  must  estimate  without  the 


26  FIRST  LESSONS  IN  METAL-  WORKING. 

help  of  these  tools,  and  must  make  allowance  for 
changes  of  size  which  the  pieces  undergo  in  draw- 
ing, and  in  other  operations  to  be  described  here- 
after. 

Estimate  the  quantity  of  iron  needed  for  the 
hook,  Pig.  20,  making  allowance  for  the  length 
gained  in  drawing,  and  cut  off  a  suitable  piece. 

Then  proceed  as  follows :  First  draw 
Exercise  11.    ^^^^  rouud  the  poiut  as  in  the  last  ex- 

A  long  hook.  .  ^ 

ercise.  Next  bend  at  right-angles  at 
aj  as  in  Exercises  5  and  6.  Then  turn  the  curve  b 
over  the  horn  of  the  anvil,  and  form  the  flat  curve  c. 


Fig.  20. 

Lastly,  form  the  eye  as  in  5  and  6,  being  care- 
ful to  have  it  in  the  same  plane  as  the  hook,  and 
circular,  and  symmetrical  on  the  stem.  In  all 
these  exercises  care  must  be  taken  to  keep  the 
iron  hot  enough  to  work  easily,  but  without  burn- 
ing it.  A  bright  white  heat  is  needed  for  draw- 
ing and  pointing,  and  a  good  red  heat  for  the  rest 
of  the  work.  In  all  the  operations  also,  care  is  to 
be  taken  not  to  mar  the  cylindrical  form  of  the 


BENDING,  POINTING,  AND  TWISTING.  27 


iron  by  liainineriiig  too  hard  ;  and  in  all  of  them, 
any  parts  that  have  been  roughened  by  the  heat 
should  be  hammered  cold  to  smooth  them^  but 
not  so  hard  as  to  injure  the  iron.  Examine  your 
work  critically,  looking  along  it  to  test  for  wind- 
ing, and  not  accepting  it  as  finished  so  long  as 
there  is  any  particular  in  which  you  can  improve 
it.  Finally,  compare  its  dimensions  carefully 
with  those  of  the  working-sketch,  so  as  to  learn 
whether  your  allowance  of  metal  was  correctly 
made. 

The  following  is  a  variation  of  the  last  exercise, 
involving  squaring  and  twisting.    The  dimensions 
are  given  in  centimeters.    The  thickness  of  the 
iron  may  be  the  same  as  in  the  last  ex-  Exercise  12. 
ercise.    After  pointing  the  rod,  form  a  twisted 
the  hook  and  the  eye  as  in  the  last 
exercise.    Then  square  the  part  ah^  Fig.  21,  with 


i 


Fig.  21. 


the  same  precautions  as  in  Ex.  4.  Finish  the 
square  part  cold,  with  good  sharp  edges.  Then 
heat  to  redness,  and  cool  both  ends  in  water, 
leaving  about  2^''  in  the  middle  bright  red  (not 


S8  FIRST  LESSONS  IN  METAL  WORKING. 


white,  wliicli  would  soften  the  iron  too  mucli). 
Holding  it  upright  in  the  vise  by  the  lower  end, 
take  hold  of  the  other  end  with  the  tongs,  and 
twist  it  round  rather  slowly,  through  exactly  two 
turns,  leaving  the  plane  of  the  eye  coincident 
with  that  of  the  hook.  Be  careful  not  to  bend 
the  stem  in  twisting  it,  as  it  will  be  hard  to 
straighten  it  without  defacing  it. 


WELDING. 


29 


LESSON  yi. 

Welding  is  Joining  two  pieces  of  metal  which 
have  been  made  soft  or  pasty  by  heat.  Wrought 
iron,  if  of  good  quality,  comes  to  this  condition  at 
the  temperature  of  about  1500°  C,  or  about  2700° 
F.  This  temperature  is  called  the  ^Svelding  heat," 
and  may  be  recognized  by  the  dazzling  white 
light  that  the  iron  gives  olf,  and  the  vivid  sparks 
that  fly  from  it  as  it  is  carried  through  the  air  to 
the  anvil.  If  the  iron  is  not  of  good  quality  it 
may  be  made  brittle  by  heat.  Such  iron  is 
called  "hot-short"  iron.  No  such  iron  must  be 
used.  Indeed,  it  is  hardly  possible  to  use  it,  but 
valuable  time  may  be  wasted  in  trying  to  do  so. 
Iron  which  breaks  under  the  hammer  when  cold 
is  called  "cold-short." 

The  sparks  given  off  by  iron  at  the  welding 
heat  show  that  it  is  burning,  and  therefore  wast- 
ing away.  This  high  temperature  therefore  must 
not  be  used,  except  when  it  is  absolutely  necessary, 
as  in  welding ;  all  other  operations  of  the  f  oige  are 
performed  at  a  "white  heat,"  a  "bright  red  or 
cherry  red,"  a  "low  red,"  or  even  a  "black  red," 
which  is  only  visible  in  a  dark  place. 


30 


FIRST  LESSONS  IN  METAL  WORKING, 


When  two  pieces  of  wrought-iron  are  to  be 
welded  together,  they  must  both  be  brought  to 
the  welding  heat ;  and  they  ought  to  reach  that 
heat  at  the  same  time,  otherwise  one  may  be 
burned  before  the  other  is  ready.  They  should 
therefore  be  heated  in  the  same  part  of  the  fire, 
and  should  be  watched,  and  if  necessary  moved 
about,  to  let  each  receive  its  proper  amount  of  heat. 
When  at  the  welding  heat,  they  must  be  put  to- 
gether as  quickly  as  possible  in  the  proper  posi- 
tion, and  made  to  adhere  by  a  few  light  blows  of 
the  hammer,  after  which  harder  blows  are  given 
till  the  union  is  complete. 

To  hold  the  two  pieces  in  the  proper  position 
and  manage  the  hammer  at  the  same  time  is  often 
difficult,  and,  even  if  the  pieces  are  not  very  large, 
generally  requires  the  hands  of  two  men,  unless 


I 


Fig.  22. 

some  device  be  used  for  fastening  tlie  two  pieces 
tog^ether.  We  will  therefore  beofin  our  exercises 
in  welding  Avith  such  as  consist  in  joining  the 


WELDING, 


31 


ends  of  the  same  piece,  and  so  do  not  require  an 
assistant.  The  forging  of  an  old-fashioned  eye 
for  a  gate-hingej  Fig.  22,  is  such  an  exercise.  To 
make  the  piece  of  the  dimensions  indicated  in  the 
figure,  cut  off  a  piece  of  f round  iron  5^'  long. 
This  is  to  be  first  flattened  and  shaped  Exercise  i3. 
as  shown  in  Fig.  23.  The  drawing  of  Flattening 
the  ends  must  be  done  at  a  red  lieat.  If  drawing, 
a  white  heat  is  used  it  will  be  harder  to  make  the 
weld  afterwards.    Turn  the  piece  over  frequently 


 9X  


Fig.  23. 

while  working  it,  to  keep  it  straight.    Do  not 
make  it  too  thin  at  the  ends.    When  flattened,  it 
should  have  in  the  middle  the  shape  and  size  shown 
in  th.e  section,  nearly,  being  flattened  Exercise  i4 
less  than  it  will  be  in  the  finished  Job,  An  eye  for  a 
for  fear  of  weakening  it  too  much,  and 
increasing  the  risk  of  burning.  Reheat  the  piece 
as  often  as  may  be  necessary,  but  take  care  not 
to  burn  it.    If  you  are  pretty  skilful,  one  or  two 
heats  will  be  enough  to  bring  it  to  the  proper 
shape.    Hammer  the  edges  square,  keeping  the 


32 


FIRST  LESSONS  IN  METAL-  WORKING, 


corners  sharp  and  smooth :  good  edges  are  as  es- 
sential to  fine  workmanship  in  metal  as  in  wood. 

Next,  heating  the  piece  to  a  dull  red  at  the  mid- 
dle, hold  it  at  one  end  with  the  tongs,  and  bend  it 
round  the  horn  of  the  anvil  till  the  two  parts  are 
parallel  and  equal,  as  in  forming  the  staple,  Exer- 
cise 9.  Put  a  piece  of  f round  iron  in  the  bend, 
and  hammer  the  two  parts  close  together,  as  at 
Fig.  22,  laying  the  piece  on  the  anvil  with  the  eye 
overhanging  the  edge,  and  striking  lightly  with 
the  tail  or  ^^pene"  of  the  hammer.  The  two  parts 
must  be  in  as  close  contact  with  each  other  as  pos- 
sible, otherwise  dirt  will  get  in  between  them,  and 
may  spoil  the  weld. 

The  piece  is  now  ready  for  welding.  Raise  it 
to  the  welding  heat.  It  is  very  essential  for  this 
operation  that  you  should  have  a  good  bright 
fire,  made  of  fresh  coals,  free  from  the  burnt-out 
cinders  on  the  hearth.  These  will  not  burn  well 
enough  to  secure  a  good  welding  heat,  and  besides 
will  make  the  surface  dirty.  The  throat  of  the 
forge  also  must  be  cleared  of  the  solid  cinder 
which  forms  there,  and  the  fire  must  be  deep 
enough  to  contain  a  good  body  of  coals  under  the 
iron  as  well  as  over  it.  When  the  piece  is  at  a 
dazzling  white  heat  and  throws  off  brilliant  sparks 
in  the  air,  place  it,  with  the  least  possible  loss  of 
time,  on  the  anvil,  and  hammer  it  quickly  with 
moderate  force  and  beginning  at  the  point,  till  it 


WELDING, 


33 


is  welded  to  within  about  of  the  eye.  Heat 
the  eye  to  a  dull  red,  drive  in  a  round  tapering 
punch  \"  in  diameter  where  thickest,  and  hammer 
harder,  at  a  dull-red  heat,  to  flatten  the  metal 
here  and  smooth  the  eye  inside  and  outside.  If 
you  have  not  a  proper  punch,  make  one,  from  a 
piece  of  round  iron  by  drawing  and  pointing  it 
slightly,  as  in  Exercises  4  and  9.  If  the  eye  is  too 
pointed  at  the  base,  close  it  by  hammering  on  the 
edge  of  the  anvil  with  the  tail  of  the  hammer 
while  the  punch  remains  in  place.  The  eye  should 
be  perfectly  round  and  smooth.  Finish  the  shank 
straight,  square,  and  smooth,  and  draw  the  tip 
down  to  a  sharp  point.  Compare  your  finished 
work  with  the  figure,  observing  how  much  you 
have  departed  from  the  proposed  dimensions.  If 
your  piece  has  turned  out  too  short,  it  is  because 
you  have  burned  it,  or  not  drawn  it  out  enough, 
or  both.  Ascertain  the  cause  of  your  error,  and 
work  closer  the  next  time. 


34  FIRST  LESSONS  IN  METAL-  WORKING, 


LESSON  VIL 

UPSETXma  AISTD  WELDIISTG. 

The  next  exercise,  the  forging  of  a  link  of  a 
chain,  is  similar  to  the  last,  in  that  the  two  surfaces 
of  the  weld  belong  to  the  same  piece,  and  thus 
again  the  need  of  a  helper  is  avoided.  The  weld, 
however,  is  much  shorter,  and  so  the  surfaces  of 
contact  are  smaller.  Besides,  as  the  link  of  a  chain 
is  subject  to  great  stress,  it  is  even  more  important 
in  this  case  than  in  the  last,  that  the  union  of  the 
two  parts  should  be  perfect.  This  therefore  will 
be  a  more  difficult  task  than  the  last. 

Use  the  piece  of  iron,  8''  long,  left  from  Ex- 
ercise 7.  The  Joint  is  of  the  form  called  a  scarf- 
Joint,  and  is  shown  in  Figs.  25  and  28.  The  sur- 
faces may  be  prepared  either  before  or  after  bend- 
ing the  piece,  but  it  is  somewhat  easier  to  make 
them  fit  together  well  if  prepared  afterwards. 
It  will  be  necessary,  however,  to  provide  against 
the  w^aste  which  will  occur  at  the  Joint  by  thick- 
ening or  upsetting"  the  piece  at  the  ends.  This 
is  an  operation  which  has  often  to  be 
Exercise  15.    performed  as  preliminary  to  others. 

UpseUing.         \  1       1  .  1        1     f.  f. 

it  may  be  done  either  beiore  or  alter 
the  bending.    To  perform  it  before  bending,  heat 


UPSETTING  AND  WELDING.  35 

about  one  inch  of  the  end  of  the  bar  to  whiteness. 
If  much  more  than  an  inch  is  heated,  cool  it,  by 
immersing  the  bar,  up  to  within  about  an  inch  of 
the  hot  end,  in  water.  Then  "upset"  the  piece 
either  by  striking  the  hot  end  on  the  anvil  while 
holding  it  upright  in  the  tongs,  or  by  standing  the 
piece  upright  on  the  anvil,  holding  it  with  the 
tongs  with  the  hot  end  up,  and  striking  the  latter 
watli  the  hammer.  In  either  case  the  blows  must 
not  be  too  hard  or  the  piece  will  bend.  The  same 
will  happen  also  if  too  much  of  the  length  of  the 
piece  is  heated.  If  the  piece  does  bend,  it  must 
be  straightened  before  going  any  farther.  If  the 
hammering  turns  the  metal  over  too  much  on  the 
edge,  lay  the  piece  on  the  anvil  and  hammer  it 
gently  on  the  sides,  but  only  enough  to  smooth 
the  ragged  edge,  without  reducing  the  end  to  its 
original  thickness.  When  properly  upset  the  end 
should  appear  as  in  Fig.  24.    After  upsetting  one 

\  1 

Fig.  24. 

end,  cool  it,  and  then  heat  and  upset  the  other. 
It  is  obvious  that  this  operation,  besides  thicken- 
ing the  bar  will  shorten  it.  You  ought  to  measure 
and  keep  a  memorandum  of  the  amount  of  this 
shortening,  so  as  to  know  how  much  to  allow  for 


36  FIRST  LESSONS  IN  METAL-  WORKING. 


it  in  other  cases,  when  it  may  be  necessary  that 
the  bar  should  have  exactly  a  given  length.  In 
the  same  way  that  a  piece  is  upset  at  the  end,  it 
may,  when  necessary,  be  upset  at  the  middle,  by 
heating  at  the  middle  only,  and  hammering  on  the 
end  leng;thwise. 

The  ends  being  now  upset,  bend  the  piece  to  a 
U -shape.  It  is  then  ready  for  the  formation  of 
the  joint. 

The  scarf -joint  consists,  as  the  figure  shows,  of 
an  indentation  in  the  end  of  each  piece,  into  which 
the  end  of  the  other  piece  fits.  These  indentations 
are  not  made,  as  in  wood-working,  by  cutting  out 


Fig.  25. 

some  of  the  material,  but  by  hammering  it  so  that 
it  spreads  out  sideways  and  endways.  Neither 
should  they,  as  in  the  case  of  the  joint  in  wood, 
be  cut  to  half  the  depth  of  the  piece,  but  less.  It 
will  thus  result  that  when  the  two  ends  are  put 
together,  the  piece  will  be  wilder  and  thicker  at 
the  joint  than  elsewhere.  This  extra  thickness 
will  disappear  as  the  weld  is  hammered,  and  if  the 


UPSETTING  AND  WELDING, 


87 


quantity  of  metal  Las  been  correctly  estimated, 
this  part  will  be  at  last  neither  thicker  nor  thin- 
ner than  the  rest. 

To  prepare  the  scarf,  heat  the  open  end  of  the 
U-shaped  piece  to  a  white  heat.  Lay  it  on  the 
anvil  and  make  a  bevel  at  one  end,  with  the  face 
of  the  hammer,  as  in  Fio;.  26.    This  will  still  fur- 

7  O 


Fig.  26. 


ther  upset  the  piece  at  the  upper  edge  of  the 
bevel,  as  shown  in  the  figure.  Then,  using  the 
pene  of  the  hammer,  as  in  Fig.  27,  give  the  piece 
the  form  shown,  enlarged,  at  a.  The  surface  need 
not  be  smooth.  It  is  indeed  preferable  that  it 
should  be  formed  of  small  ridges  or  steps  as  shown. 
Heat  the  other  end  of  the  piece  and  treat  it  in  the 
same  manner,  but  on  the  other  side.  One  heat 
will  be  sufficient  for  the  preparation  of  both  ends 
if  you  Avork  quickly,  but  there  will  be  no  harm 
in  heating  several  times,  if  you  are  careful  not  to 


38 


FIRST  LESSONS  IN  METAL-WOUKING, 


burn  the  piece.  The  pieces  will  have  been 
widened  in  the  process  of  scarfing,  and  are  to  be 
brought  back  partly  to  their  original  Avidth,  by 
hammering  on  the  sides.  There  should  be,  how- 
ever, some  extra  width  left,  to  make  up  for  the  loss 
by  burning,  of  which  there  will  be  some  in  spite 
of  all  the  care  that  can  be  taken.  When  finished, 
the  scarf  will  present  the  a2:>pearance  shown  in 
plan  and  elevation  in  Fig.  28. 


Fig.  27.  Fig.  28. 


When  the  scarf  has  been  thus  prepared,  bend 
the  ends  of  the  V  round  over  the  horn  of  the 
anvil  as  in  Fig.  29,  till  they  meet  and  overlap,  as 
in  Fig.  30,  and  hammer  tliem,  at  a  red  heat,  now 
on  the  face  of  the  anvil  and  now  on  the  horn,  till 
they  fit  together  closely.  You  are  now  ready  for 
the  welding. 

Foi'  this  make  sure,  as  in  the  last  exercise,  that 
you  ha\^e  a  hot  fire  of  good  coals,  and  get  a  thor- 


UPSETTING  AND  WELDING, 


39 


ough  good  welding  lieat^  without  burniDg.  There 
is  special  danger  of  burning  in  exercises  like  this, 
in  which  the  piece  is  small,  and  has  a  thin  edge. 


Fig.  29. 


As  soon  as  it  shows,  by  the  vivid  sparks  which  it 
emits,  and  by  its  intense  whiteness  Avhen  viewed 
through  the  chinks  in  the  fire,  that  the  proper 
heat  has  been  reached,  place  it  as  quickly  as  pos- 
sible on  the  anvil,  and  hammer  the  parts  together 
by  quick  light  blows.    When  they  have  adhered, 

}  ^1=3 

Fig.  30. 

the  extra  metal  produced  by  the  upsetting  and 
scarfing  may  be  hammered  down  on  the  horn  of 
the  anvil,  and  the  link  brought  to  its  proper  shape, 
more  at  your  leisure  and  at  a  lower  heat. 


40  FIRST  LESSONS  IN  METAL- WORKINO. 


Ill  this  exercise,  and  in  general  in  all  welding 
operations,  it  is  necessary  that  the  surfaces  of  con- 
tact should  be  quite  clean,  or  if  there  is  anything 
on  them,  it  should  only  be  something  fusible, 
Avhich  will  squeeze  out  under  the  blo\vs  of  the 
hammer.  Coal-dust  will  generally  burn  off  and 
not  give  nuich  trouble.  Cinders,  if  your  fire 
should  be  so  dirty  "  as  to  allow  any  to  settle  on 
the  joint,  which  ought  not  to  happen,  can  often 
be  shaken  off  by  a  sharp  blow  on  the  edge  of  the 
anvil.  The  oxide  of  iron  also,  in  the  intense  heat 
of  the  welding  fire,  is  generally  driven  off  as  fast  as 
it  is  formed.  But  while  the  piece  is  exposed  to  the 
air  on  the  anvil,  and  on  its  way  there,  some  oxide  of 
iron  is  formed  which  is  not  got  rid  of,  but  which 
falls  off  under  the  blows  of  the  hammer,  and  is 
found  on  the  anvil  as  black  scales.  If  any  of  this 
forms  on  the  surfaces  of  contact,  or  if  any  cinder 
is  held  between  these  surfaces  during  the  weld- 
ing, the  iron  will  not  adhere  well,  and  the  weld 
will  fail.  This  therefore  is  another  reason  why 
you  should  work  quickly  at  this  stage. 

This  oxide  of  iron,  when  its  formation  cannot 
be  prevented,  is  removed  by  the  use  of  white  sand 
or  boi  *ax  as  a  flux,"  that  is,  a  substance  which 
unites  with  the  oxide  and  makes  a  sort  of  glass, 
which  is  fusible  and  is  squeezed  out  by  the  ham- 
mer. With  good  wrought-iron  the  flux  is  not 
generally  necessar} ,  provided  a  true  welding  heat 


UPSETTING  AND  WELDING. 


41 


is  used  and  tlie  work  is  done  quickly.  With 
steel,  as  Avill  be  seen  hereafter,  it  is  indispensable. 
When  a  flux  is  used  with  wrought-iron,  it  is  to  be 
sprinkled  on  the  Joint,  or  the  iron  is  to  be  plunged 
in  the  flux,  but  only  at  the  welding  heat.  At  a 
lower  temperature  the  sand  will  not  adhere  and 
melt,  and  will  do  no  good.  At  the  welding  heat 
it  melts  and  spreads  over  the  surface,  partially 
protecting  it  from  the  air,  and  allowing  it  to  be 
raised  to  a  higher  temperature  without  burning 
so  much.  When  it  is  put  into  the  fire  again,  the 
brilliant  white  sparks  still  appear,  and  as  it  is 
carried  to  the  anvil  it  will  give  forth  a  hissing 
noise.  When  this  happens  you  are  pretty  sure  of 
a  good  weld  if  you  work  quickly. 

The  form  of  the  Joint  is  important  also,  with 

\  ^srz3- 

\  ^  

Fig.  31. 


reference  to  the  escape  of  impurities.  If  the  sur- 
faces of  the  scarf  are  concave,  as  in  Fig.  31,  a, 


42 


FIR8T  LESSONS  IN  METAL-  WORKING. 


the  welding  takes  effect  first  at  the  two  points  of 
contact  shown,  and  some  of  the  impurities  may  be 
imprisoned,  and  prevent  a  good  union  of  the  pieces, 
though  in  general  they  will  escape  sideways,  par- 
ticularly if  the  surfaces  are  small.  If  the  surfaces 
are  convex,  as  at  b,  they  touch  at  first  only  at 
the  middle,  and  there  is  sure  to  be  plenty  of  op- 
portunity for  the  impurities  to  escape,  however 
large  the  surfaces  may  be.  The  same  result  is 
secured  nearly  as  well  if  the  surfaces  at  a  are  put 
toa;ether  in  the  manner  shown  at  c. 

It  is  desirable  that  the  weld  should  be  accom- 
plished at  a  single  heat,  because  in  reheating  the 
danger  of  burning  is  increased ;  but  you  must  not, 
merely  to  avoid  this  risk,  allow  an  imperfect  weld 
to  pass. 

Inspect  your  work  critically  when  done.  It 
should  show  the  following  appearances : 

1.  The  weld  should  be  invisible. 

2.  The  iron  should  not  be  burned  away  at  the 
thin  edges  of  the  scarf,  leaving  little  notches ;  yet 
this  is  a  less  serious  fault  than  if  the  scarf  itself  is 
visible  as  a  fine  crack  for  the  whole  or  a  part  of 
its  length. 

3.  The  ring  should  not  be  any  thicker  at  the 
weld  than  elsewhere,  nor  any  thinner, — which  is 
more  likely  to  happen,  and  is  a  more  serious  fault. 

4.  The  iron  should  be  of  circular  cross-section 
throughout,  and  without  bruises, 


UPSETTING  AND  WELDING, 


43 


5.  The  link  should  be  a  perfect  ellipse,  and 
with  the  7-inch  piece  of  iron  that  you  have  used, 
should  be  of  the  exact  size  and  shape  of  Fig.  32, 


Fig.  32.    (Full  size.) 


If  the  iron  is  too  much  reduced,  or  the  weld 
bad,  cut  out  the  imperfect  part,  and  repeat.  This 
will,  of  course,  make  the  link  too  small.  After- 
wards, take  a  new  piece,  and  try  again. 

The  scarfed  surfaces  in  this  exercise  may  be 
prepared  in  another  way,  using  the  face  of  the 


Fig.  33. 

hammer  instead  of  the  pene.  Having  upset  and 
bent  the  piece  as  before,  lay  it  on  the  anvil  as  in 
Fig.  33,  only  about  half  an  inch  of  the  ends  rest- 


44  FIRST  LESSONS  IN  METAL  WORKING, 


ing  on  the  anvil.  With  a  full  red  heat,  strike  a 
blow  or  two  on  one  end,  holding  the  face  of  the 
hammer  parallel  to  that  of  the  anvil.  Draw  the 
piece  toward  you  about  and  strike  again. 
Repeat  this  operation  out  to  the  end  of  the  piece, 
then  turn  it  over  and  treat  the  other  end  the  same 
way.  The  edge  of  the  anvil  thus  serves  the  same 
purpose  as  the  pene  of  the  hammer  in  the  pre- 
vious method.  In  this  case  also,  as  before,  the 
piece  must  be  lightly  hammered  on  the  sides  to 
partially  correct  the  spreading. 


BLACKSMITH  AND  HELPER, 


45 


LESSON  VIIL 

BLACKSMITH  AND  HELPEE. 

You  will  now  Join  two  separate  pieces  by  a 
scarf-joint.  In  this  case,  both  pieces,  when  pre- 
pared and  heated,  will  have  to  be  held  in  tongs 
to  bring  them  together.  If  one  workman  attempts 
to  do  this,  he  has  to  lay  down  one  pair  of  tongs 
and  take  np  his  hammer,  and  thus  runs  the  risk 
of  having  one  piece  fall  out  of  its  place,  or  both 
pieces  get  chilled.  The  operation  is  therefore 
much  more  easily  performed  with  the  aid  of  a 
helper,"  who  follows  the  lead  of  the  other  work- 
man, called  the  blacksmith  "  or  '^fireman,"  strik- 
ing and  stopping  as  the  latter  directs,  and  work- 
ing the  bellows  while  the  other  manages  the  fire. 
A  skilful  workman  can  indeed  perform  this  task 
without  a  helper,  particularly  with  the  aid  of  cer- 
tain devices  to  be  described  presently;  but  many 
other  operations,  particularly  on  heavy  pieces,  are 
impossible  without  a  helper. 

Cut  two  pieces  of  V  square  iron,  each  5'^  long. 
If  you  fail  to  do  this  exactly,  make  a  memoran- 
dum of  the  exact  amount  of  your  error,  that  you 
may,  when  the  work  is  finished,  learn  how  much 
has  been  used  up  in  the  weld,  and  therefore  be 


46  FIRST  LE8S0N8  IN  METAL-  WORKING. 


able  to  make  the  proper  allowance  for  such  a  joint 
in  the  future. 

Place  both  pieces  with  one  end  in  the  fire,  but 
bring  only  one  at  a  time  to  a  white  heat.  Hav- 
ing the  services  of  a  helper,  we  will 
Exercise  16.    ^^-^  time  prepare  the  scarf  with  the 

Use  of  fuller.  »  .  . 

tool  called  a  "  top-fuller."  This  is  a 
tool  very  much  like  the  pene  of  your  hammer,  the 
edge  being  set  (as  may  also  be  the  case  with  the 
hammer)  either  parallel  or  perpendicular  to  the 
handle.  It  is  held  in  one  hand  by  the  blacksmith, 
and  struck  with  a  heavy  hammer,  or  sledge,"  by 
the  helper,  while  it  rests  on  the  part  of  the  piece 
which  is  to  be  indented.  As  an  unskilful  blow 
may  give  a  painful  Jar  to  the  hand  of  the  holder, 
the  handle  of  this  or  any  similar  tool  is  sometimes 
made  of  twisted  wire,  or  even  of  a  withe  or  rod 
of  hazel  or  other  flexible  wood.  The  rod  is  sev- 
eral times  wetted,  heated,  and  twisted  at  the  mid- 
dle, to  loosen  the  fibres  of  which  it  is  composed. 
It  is  then  passed  once  or  twice  round  the  head  of 
the  tool,  twisted,  and  held  in  place  by  a  small  iron 
ring,  as  in  Fig.  34.  With  this  flexible  handle  the 
hand  of  the  holder  is  safe  from  shocks.  A  similar 
tool,  with  the  edge  turned  upward  and  shaped  like 
the  hardee,  so  as  to  be  set  in  the  anvil,  is  called  a 
"  bottom-fuller." 

To  make  the  scarf -joint  with  this  tool,  the  fire- 
man brings  the  end  of  the  piece  to  a  white  heat, 


BLACKSMITH  AND  HELPER. 


47 


as  before,  and  bevels  and  upsets  it,  as  in  Figs.  24 
and  26.    Then,  taking  the  fuller   in  the  right 


Fig.  34. 


Fig.  35. 


hand,  he  holds  it  on  the  bevelled  surface,  as  in 
Fig.  35,  while  the  helper  strikes  it  with  the  sledge. 
It  is  easy  to  see  that  this  tool  can  be  guided  with 
more  accuracy  than  the  pene  of  the  hammer. 
With  this  the  two  pieces  are  brought  to  the  form 
shown  in  Fig.  31  B.  They  are  then  laid  in  the 
fire,  the  scarfed  surfaces  downward,  that  no  dirt 
may  fall  on  them  as  they  are  removed  from  the 
fire,  and  as  close  together  as  they  can  be  placed 
without  touching,  in  order  that  they  may  arrive  at 
the  welding  heat  at  the  same  time.  They  must  not 
touch,  however,  as  they  would  adhere  in  the  fire. 
When  they  have  been  sprinkled  with  „      .  ,„ 

^  ^  ,         Exercise  17. 

sand  and  brought  to  the  full  welding  scarf-joint 

heat,  they  are  taken  quickly  from  the 

fire,  first  one  piece  by  the  helper  and 

then  the  other  by  the  blacksmith.    The  helper 


48 


FIRST  LESSONS  IN  ME2 AL-WORKINO. 


goes  first,  because  his  place  is  on  the  farther  side 
of  the  anvil,  while  the  blacksmith  stands  between 
the  anvil  and  the  fire.  The  helper  strikes  with 
his  piece  a  sharp  blow  on  the  edge  of  the  anvil 
farthest  from  him,  to  knock  off  any  cinders  that 
may  be  on  it^  and  then  rests  it  on  the  near  edge,  as 
in  Fig.  36,  the  scarf  surface  up,  but  being  very 


Fig.  36. 


careful  not  to  let  the  thin  edge  of  the  iron  touch 
the  anvil,  which  w^ould  chill  it.  The  blacksmith 
follows  quickly  with  his  piece,  knocking  off  dirt 
in  the  same  way,  and  places  it  on  the  first  piece, 
as  in  Fig.  37.    It  is  of  the  utmost  importance  that 


Fig.  37. 

the  first  piece  be  neld  quite  steady,  and  the  second 
placed  on  it  in  exactly  the  right  position.  If  it 
laps  a  little  too  much  or  not  quite  enough,  the 
scarf  will  turn  out  bad.    The  thin  edges,  which 


BLACKSMITH  AND  HELPER. 


49 


may  have  cooled  a  little  in  the  air,  are  heated  again 
by  contact  with  the  tliicker  parts.  A  quick  light 
blow  or  two  at  h  by  the  blacksmith,  will  make  the 
iron  adhere.  The  blacksmith  turns  the  piece  over 
and  makes  it  adhere  at  a  in  the  same  way.  It  is 
then  laid  flat  on  the  anvil,  as  in  Fig.  38,  and  welded, 


Fig.  38. 


with  heavier  blows,  by  blacksmith  and  helper 
together,  the  former  with  his  hammer,  the  latter 
with  a  sledge.  The  blacksmith  strikes  wherever 
he  considers  it  best,  and  turns  the  piece  when 
necessary,  and  the  helper  follows  him,  striking  at 
tlie  same  point,  and  beginning  and  stopping  when 
the  blow  of  the  blacksmith's  hammer  on  the  piece 
or  on  the  anvil  gives  the  signal.  Test  the  weld 
before  finishing.  Holding  one  end  of  the  piece 
with  the  tongs,  strike  it  at  the  middle,  while  hot, 
over  the  horn  of  the  anvil,  bending  it,  and  then 
again  straightening  it  or  bending  it  the  opposite 
way.  The  weld  should  not  open  under  such  treat- 
ment. If  the  weld  is  satisfactory,  the  piece  is  fin- 
ished smooth  and  square  with  the  flatter,"  Fig. 
39,  which  is  held  on  the  bar  by  the  blacksmith  and 
struck  by  the  helper.    With  this  tool,  of  course^ 


50 


FIRST  LESSONS  IN  METAL-  WOUKING. 


a  better  finish  is  possible  than  with  the  hammer 
Exercise  18.  The  bar  should  be  tested  at 

Use  of  the  the  weld  with  calipers  and  square, 
flatter.  made  perfectly  straight.  After 

this  it  may  be  finished  smooth  and  partially  pol- 
ished, by  dipping  the  face  of  the  flatter  in  water 


Fig.  39. 

and  slightly  wetting  with  it  the  face  of  the  anvil 
during  the  last  part  of  the  hammering. 

The  result  of  the  work  should  be — 

1°.  A  perfectly  straight  bar; 

2"".  Of  uniform  cross-section  of  \" \ 

3°.  Perfectly  square ; 

4°.  Without  any  twist ; 

5°.  With  no  visible  or  a  scarcely  visible  weld ; 

6°.  Nowhere  burnt; 

7°.  Quite  smooth  and  polished;  and, 

8°.  Exactly  11^^  long. 

If  its  length  differs  from  that  given,  it  is  be- 


BLACKSMITH  AND  BELPEB. 


51 


cause  you  did  not  cut  the  pieces  to  the  right 
length,  or  because  you  have  used  up  too  much 
material  in  welding.  In  either  case  note  the 
facts  in  your  memoranda^  and  be  forewarned  for 
the  next  task  of  the  kind. 


52 


FIRST  LESSONS  IN  METAL-  WORKING. 


^  LESSON  IX. 

WELDING   (cONTIlSrUED).     A  TONGUE-WELD. 

The  scarf -weld  Just  practised  is  an  excellent 
Joint,  and,  for  most  purposes,  as  good  as  can  be 
desired.  For  many  heavy  pieces,  sucli  as  shafts 
of  steamers,  the  tongue-Joint,  Fig.  40,  is  often 

Fig.  40. 

used,  and  even  in  smaller  work,  such  as  the  re- 
pairing of  a  broken  wagon-axle,  it  is  useful. 
Moreover,  it  can  be  more  easily  managed  without 
the  aid  of  a  helper  than  the  scarf -joint  can.  We 
will  exemplify  it  with  pieces  of  the  same  size  as 
those  used  in  the  last  exercise.  Cut  them,  as  be- 
fore, to  the  exact  length,  or  record  the  error. 

Heat  the  pieces,  and  hammer  one  of  them  out 
on  the  edge  of  the  anvil,  to  the  wedge-form.  Fig. 
41,  A.  The  hammering  will  spread  "  or  widen 
the  piece  on  the  edge,  as  shown  in  the  plan  b. 
This  widening  is  to  be,  for  the  present,  only  very 
slightly  reduced,  by  hammering  on  the  sides. 

Upset  the  other  piece  as  in  the  last  exercise, 


WELDING.    A  TONQVE-WELB,  53 


giving  it  the  appearance  shown  in  Fig.  42,  a. 
This  piece  is  now  to  be  split  and  opened,  as 


Fig.  41.  Fig.  42. 


shown  in  Fig.  42,  b,  to  a  depth  equal  to  the 
length  of  the  wedge.  It  is  important  that  the 
opening  should  be  of  this  depth,  otherwise  a 


Fig.  43.  Fig.  44. 

portion  of  the  reduced  thickness  of  the  wedge 
will  be  left  exposed,  and  the  piece,  when  finished, 


54 


FIRST  LES80N6  IN  METAL-  WORKING, 


will  be  too  small  at  this  point.  If,  on  the  other 
hand,  the  cut  is  too  deep,  the  wedge  will  go  in  too 
far,  and  the  piece  will  be  shortened,  besides  being 
thickened  at  the  joint.  The  slit  is  made  with  a 
'-^  hot  chisel,"  Fig.  43,  that  is,  a  chisel  adapted  to 
the  cutting  of  hot  iron.  While  the  piece  is  at  a 
bright  red  or  white  heat,  the  blacksmith  holds  it 
on  the  edge  of  the  anvil,  as  in  Fig.  44,  and  holds 
the  chisel  on  the  line  of  the  proposed  cut,  and  the 
helper  drives  the  chisel  in  with  blows  of  the 
sledge.  The  workman  does  not  try  to  make  the 
whole  length  of  the  cut  at  once,  but  begins  at  the 
end,  and  w^orks  gradually  inward.  When  the  cut 
is  about  half-way  through,  he  turns  the  piece  over 


Fig.  45. 

and  works  from  the  other  side.  The  cut  being 
Exercise  19  i^^^clc,  it  may  be  widened  by  setting 
A  split  or  the  piece  on  end,  witli  the  cleft  up, 
v-weid.  .^^j  driving  the  chisel  into  it,  or  l)y 
setting  it  up  with  the  cleft  down,  and  driving  it 


WELDING,    A  TONOUE-WELD. 


55 


on  the  liardee,  or  on  a  bottom-fuller.  When  the 
piece  has  been  split,  hammer  out  the  edges  of  the 
Jaws  a  little,  as  in  Fig.  45,  thinning  them  only  a 
little,  and  then  close  the  Jaws  again,  partly,  as  in 
Fig.  46.    If  you  have  no  helper,  tlie  whole  opera- 


FiG.  46. 


tion  may  be  performed,  tliougli  not  quite  so  easily, 
on  the  liardee  and  a  bottom-fuller,  or  even  by 
holding  the  piece  in  the  vise,  and  splitting  it  with 
a  chisel. 

The  split  piece,  or  V-piece,  being  now  again 
heated  to  whiteness,  the  blacksmith  holds  it  up- 
right on  the  anvil  w^ith  one  pair  of  tongs,  and  the 
cold  w^edge-piece  with  another  pair,  w^hile  the 
helper  drives  it  in  gently.  The  wedge  must  enter 
to  its  full  depth,  and,  if  necessary,  the  cut  must 
be  extended  for  this  purpose,  for  the  reason  al- 
ready given.  It  must  also  go  quite  to  the  bottom 
of  the  cut,  otherwise  a  hole  wall  be  left  in  the 
finished  piece  at  that  point. 

The  wedge  being  quickly  driven  in  to  its  proper 


56  FIRST  LESSONS  IN  METAL-WORKING. 


deptn,  the  pieces  are  turned  over  on  tlieir  side, 
and  the  jaws  of  the  slit  hammered  down  closely 
on  the  Avedge,  the  blacksmith  and  helper  push- 
ing the  pieces  firmly  together  all  the  time,  to  pre- 
vent the  wedge  from  slipping  out.  The  ears  a 
and     Fig.  47,  b,  which  project  beyond  the  edges 


a 

b 

Fig.  47. 

of  the  wedge-piece,  are  to  be  turned  down  round 
it,  thus  holding  the  two  pieces  together  while  the 
weld  is  being  finished.  The  two  pieces  thus 
joined  together  are  laid  in  the  fire  and  brought 
to  a  welding  heat.  Two  or  three  blo^vs  struck 
lengthways  will  make  the  weld  secure  at  the 
middle.  Then  reheat,  and,  blacksmith  and  helper 
together  pushing  strongly  towards  each  other,  fin- 
ish the  weld  while  the  piece  lies  on  its  side  and  is 
turned  to  and  fro  by  the  former. 

The  finishing  is  effected  in  the  same  way  as  in 
the  last  exercise,  and  the  same  tests  are  applied  to 
the  work. 


WELDING.    A  TONGUE-WELD. 


57 


This  joint  can  be  made  by  one  workman  alone, 
if  lie  is  skilful  and  the  pieces  are  not  too  large. 
He  will  cut  the  slit  on  the  hardee,  or  in  the  vise 
with  a  chisel.  To  drive  the  cold  wedge  into  the 
V  J  he  will  hold  the  V  -piece,  red-hot,  upright  in 
the  vise,  and  holding  the  cold  wedge-piece  in  the 
hand,  drive  it  in  with  the  hammer.  He  will  then 
squeeze  the  jaws  of  the  V  together  with  the 
tongs,  and  turn  the  ears  over  the  wedge  by  light 
blows  of  the  hammer  on  the  anvil.  ,The  two 
pieces  should  then  hold  together  firmly  enough  to 
allow  of  handling  them  (with  care)  in  the  fire, 
while  being  heated  for  the  weld. 

The  V-weld,  or  split-weld,  is  especially  valua- 
ble for  very  large  pieces.  -With  such  pieces,  after 
the  joint  has  been  formed  and  the  two  pieces  have 
been  fitted  together,  and  while  they  are  at  a  weld- 
ing heat  in  the  fire,  they  are  partly  welded,  with- 
out removing  them  from  the  fire,  by  blows  of  a 
heavy  sledge  on  the  end.  Only  the  finishing  of 
the  weld  has  then  to  be  done  on  the  anvil. 


58  FIRST  LESSONS  IN  METAL-WORKING, 


LESSON  X. 

TESTING  IRON.     MANUFACTURE  OF  CAST-IRON. 

Bars  welded  by  any  of  these  methods  should  be 
almost  as  strong  as  bars  without  welds.  They  can 
be  readily  tested  in  a  machine  such  as  that  used 
in  the  Lessons  on  Wood-working,  only  larger  and 
stronger.  Such  machines  are  made  of  sufficient 
power  to  break  a  bar  of  wrought-iron  five  inches 
in  diameter.  The  small  machine  w^ill  serve  for 
testing  wires,  and  such  pieces  as  were  used  in 
your  first  exercises  ;  and  you  should  now  make  a 
few  welds  with  such  iron  and  test  them,  compar- 
ing their  strength  with  that  of  the  solid  bar. 

Put  one  of  these  pieces,  J''  square,  into  the  ma- 
chine, and  apply  a  gradually  increasing  force  till 
the  piece  breaks.  The  cross-section  being  of  a 
Exercise  20.  square  iuch,  the  ^'  tensile  strength" 
Testing  bars  or  tenacity"  of  the  iron  per  square 
and  welds.  gi^tcen  timcs  the  amount  that 

the  testing-machine  indicates.  If  the  bar  were 
round  and  \"  in  diameter  its  cross-section  would 
be  about  GWVO?  ^^^^  tenacity  about  20 
times  that  of  the  specimen.    This  strength  varies, 


TESTING  IRON.    MANUFACTURE  OF  CAST-IRON  59 


for  (lifterent  kinds  of  wrougbt-irorij  from  35,000 
to  55,000  lbs.  It  is  usually  higlier  for  iron  wire 
than  for  bar-iron,  because  none  but  the  best  qual- 
ity of  iron  can  be  used  for  making  wire,  and  be- 
sides, the  "  drawing"  of  the  wire  lengthens  and 
compresses  tlie  fibres,  thus  giving  additional 
strength.  Test  two  or  three  specimens  of  wire, 
and  calculate  their  tensile  strength. 

The  tensile  strength  of  wrought-iron  is  not 
the  only  important  quality  that  can  be  tried  and 
measured  in  the  testing-machine.  Good  wrought- 
iron  should  have  great  ductility,  that  is,  it  should 
sulfer  considerable  stretching,  and  consequently 
considerable  reduction  of  cross-section,  before 
breaking.  If  it  does  not,  it  is  not  fit  for  use  in 
such  a  structure,  for  instance,  as  an  iron  bridge, 
because  when  a  great  stress  is  put  upon  it,  in- 
stead of  stretching,  and  so  giving  warning,  it  will 
break  suddenly.  It  is  usual,  therefore,  with  en- 
gineers to  require  that  the  iron  to  be  used  in 
bridges,  shall  suffer  an  elongation  of  12  to  20  per 
cent  and  a  reduction  of  cross-section  Exercise  21 
of  30  per  cent  before  breaking.  Mea-  Test  of 
sure  the  diameter  of  the  section  of  the  ^^^*^i^*^y- 
broken  rod  at  the  point  of  rupture,  compute  its 
area,  and  the  percentage  of  reduction. 

Besides  tenacity  and  ductility,  good  wrought- 
iron  has  great  hardness  and  stiffness,  that  is,  it  re- 
quires great  force  to  crush  it  or  to  bend  it.  Test 


60 


FIRST  LESSONS  IN  METAL-WORKING. 


a  specimen  of  wi*ouglit-iron  in  these  respects  in 
the  machine,  and  record  the  ]*esults  for  compari- 
son hereafter  with  cast-iron  and  with  steel.  You 
will  find  that  Avhile  different  kinds  of  wronght- 
iron  differ  from  each  other,  they  are,  on  the  aver- 
age, superior  in  all  these  respects  to  cast-iron. 

The  differences  between  cast-iron,  wrought-iron, 
and  steel,  and  between  different  specimens  of 
each,  result  from  their  composition  and  mode  of 
manufacture.  Cast-iron  is  a  mixture  of  iron  with 
about  4  to  7  per  cent  of  carbon,  which  makes  it 
fusible  at  about  1100°  C.  or  about  2500°  F.  It 
generally  contains  also,  small  quantities  of  othei* 
substances,  as  sulphur,  silicon,  and  phosphorus, 
which  have  various  effects  on  its  fusibility,  its 
ductility,  and  its  hardness.  As  moi*e  and  more 
of  the  carbon  is  removed,  the  iron  becomes  first 
steel  and  then  wrought-iron,  endless  varieties  of 
each  I'esulting  from  the  kind  and  quantity  of  the 
im]3urities.  The  way  in  which  these  substances 
find  their  way  into  the  product,  and  the  means  by 
which  they  are  removed,  will  be  understood  from 
a  brief  description  of  the  methods  of  manufactur- 
ing cast-iron,  wrought-iron,  and  steel. 

The  broken-up  ore  is  placed  in  a  structure  forty  - 
to  eighty  feet  high,  called  a  ^'blast-furnace,"  shown 
in  Fig.  48,  in  layers  alternating  with  layers  of 
coal  or  charcoal  and  of  broken  limestone.  The 
coal  beino;  imited  and  a  strono;  blast  of  air  driven 


TESTING  IRON.    MANUFACTURE  OF  CAST-IRON.  61 


through  the  iron  pipes  or 
the  furnace  near  the  bot- 
tom, the  heat  melts  the 
material  above,  which 
flows  off  below  tlirough 
the  opening  shown  in  the 
flgure.  Fresh  layers  are 
added  above,  and  thus  the 
furnace  is  kept  in  con- 
stant action,  for  months 
or  years,  till  it  becomes 
necessary  to  let  the  fire 
out  in  order  to  make  re- 
paii'S. 

The  use  of  the  coal  in 
this  operation  is  evident. 
That  of  the  limestone  is 
to  form  an  easily  fusible 
mixture  with  the  silica  or 
sand  and  the  earthy  mat- 
ter of  the  ore,  and  cause  it 
to  flow  off.  At  the  same 
lime  some  of  the  carbon  of 
the  fuel  Joins  with  the  iron 
and  makes  another  fusible 
mixture,  cast-iron.  There 
are  thus  two  fluids  con- 
stantly accumulating  in 
the  bottom  of  the  furnace. 


tuyeres"  which  enter 


Fig.  48 

The  lieavier  one  settles 


62 


FIRST  LESSONS  IJST  METAL-  WORKING. 


to  the  bottom,  and  is  drawn  off  from  time  to 
time,  tlirougli  an  opening  made  for  the  purpose,  as 
cast-iron.  The  lighter  one  floats  above  this,  and 
is  drawn  off  through  another  opening,  as  ^^slag"  or 
cinder."  When  cold,  it  is  usually,  though  not 
alw^ays,  broken  up  and  thrown  away  as  a  waste 
product. 

The  iron  thus  obtained  from  the  furnace  flows 
down  a  trough  A  A  in  a  bed  of  sand  on  the  floor 
to  the  troughs  BB^  and  thence  into  the  moulds 


B  B  B 


A 


Fig.  49. 

CO.  One  of  the  groups  composed  of  B  and  C  is 
called  a  sow  and  pigs,"  and  the  pieces  each 
of  which  is  about  three  feet  long  and  contains 
about  100  lbs.  of  iron,  is  called  a  "pig." 

The  "  pig-iron"  thus  produced  contains  various 
impurities,  according  to  the  kinds  of  ore,  lime,  and 
fuel  used.  The  study  of  the  various  grades  of 
pig^ron  would  lead  us  farther  than  we  can  go  at 
present,  fhey  are  designated,  in  part,  by  tl^e 
name  of  the  country  or  district  in  which  they  are 


TESTING  IRON.    MANUFACTURE  OF  CAST-IRON  63 


produced,  or  the  furnace  producing  tliem — Norway, 
Cumberland,  Lownioor,  Warwick,  Salisbury.  Be- 
sides this,  they  are  also  divided  into  three  princi- 
pal grades  used  for  different  purposes.  These 
are : 

No.  1,"  which  is  coarse  grained  and  very  dark 
and  soft,  and  is  used  for  foundry- work  ; 

^^No.  2,"  which  is  less  coarse,  but  still  dark  and 
soft,  and  is  also  used  for  foundry- work ; 

No.  3,'^  or  Gray  Forge,  also  sometimes  called 
No.  1  Mill ; 

"  Mottledj^'' w\\\q\i  is  light  gray  with  specks  of 
white  ;  and, 

"  White^^''  which  is  white  all  over. 

The  last  three  are  used  for  reheating  and  manu- 
facturing into  refined  iron,  as  explained  in  Lesson 
XII. 


64 


FIRST  LESSONS  IN  METAL-WORKING, 


LESSON  XL 

rOUKDRY-WORK. 


Exercise  22, 
Making  a 
pattern. 


Cast-iroi^"  is  readily  fusible,  and  a  great  many 
articles  are  made  directly  from  it  in  the  ^^iron-foun- 
dry," different  kinds  of  pig  being  mixed  together 
to  obtain  the  desired  quality.  To  illustrate  the 
method  of  casting  or  founding  in  metal,  which  is 
the  same  in  its  essentials,  whether  the 
metal  be  iron,  steel,  brass,  or  zinc,  we 
will  casta  small  object  in  brass,  which 
can  be  melted  in  your  forge-fire  or  in  that  of  a 
small  portable  furnace,  while  iron  would  require 
a  much  higher  temperature.  We  will  take  for 
the  object  the  square  prism  shown  in  isometric 
projection  in  the  sketch,  Fig.  50,  to 
be  used  in  a  later  exercise.    The  rou^-h 

o 

casting  must  be  a  little  larger  than  it 
is  shown  in  the  sketch,  to  allow  for 
waste  in  finishing.  The  amount  of 
the  difference  depends  on  the  fine- 


FiG.  50.       ness  of 


IS  very 


rough. 


the 
may 


castmg. 


be 


If  the  casting 
lost  on  each  face; 


FO  UNDB  Y-  WORK, 


65 


if  very  smootli^  less  than  maybe  enough.  As 
we  shall  perform  several  operations  on  the  casting 
before  finishing  it,  we  will  make  the  casting 
square  and  long.  If,  however,  we  make  a 
mould  of  this  size,  the  metal  when  poured  into  it 
will  shrink  in  cooling,  and  make  the  piece  too 
small.  It  is  usual,  as  the  result  of  experience,  to 
allow  about  1  per  cent  or  about  to  a  foot  for 
shrinkage  ;  but  this  allowance,  which  is  impoi'tant 
in  large  pieces,  may  be  neglected  in  so  small  a 
work  as  the  present. 

If  the  pattern  were  made  of  the  size  and  shape 
thus  far  determined  on,  you  would  find,  on  trying 
to  perform  the  next  operation,  that  you  would 
fail.  After  packing  the  sand  round  your  pattern 
in  the  mould,  you  would  find  that  the  pattern 
would  not  draw,''  that  is,  it  could  not  be  lifted 
from  the  sand  without  breaking;  down  the  mould 
It  must  be  a  little  thinner  on  that  side  which  is 
set  deepest  in  the  sand.  The  least  taper  that  wdll 
suflice  for  this  purpose  is  about  in  a  foot,  or 
about  j^^'  in  an  inch.  Allowing  something  more 
than  this  in  this  very  small  piece,  you  may  make 
one  face  of  your  pattern  about  ^vider  than  the 
opposite  face.  Finish  up  the  pattern  as  smooth 
as  you  can  make  it,  and  give  it  a  smooth  coat  of 
shellac  varnish. 

The  process  of  moulding"  consists  in  making 
a  depression  in  sand,  of  the  size  and  shape  of  the 


66  FIRST  LESSONS  IN  METAL- WORKING. 


pattern,  and  that  of  "  casting^'  consists  in  filling 
this  depression  with  the  melted  metal.  The  sand 
must  be  very  firm,  and  Just  moist  enough  to 
"  pack/'  or  stick  together  slightly  when  squeezed 
in  the  hand.  If  it  is  moister  than  this,  it  may 
cause  accidents  by  the  sudden  generation  of  steam 
when  the  melted  metal  is  poured  into  the  mould. 
The  sand  is  held  in  place  while  it  is  being  packed 
round  the  pattern,  by  a  moulding-box  or  "  flask," 
of  wood  or  iron,  formed  in  two  parts,  which  can  be 
separated  and  put  together  again  in  exactly  the 
same  position,  being  guided  by  two  pins  in  one 
part,  which  pass  through  two  holes  in  correspond- 


A 

— 

P 

B 

Q 

J  C 

A 

J  C 

B 

_TrQ 

->  c 

Fig.  51. 

ing  ^'lugs"  on  the  other.  Each  part  is  accom- 
panied by  a  flat  moulding-board  "  about  two 
inches  longer  and  wider  than  the  flask,  with 
"  tongue-and-grooved "  strips  across  the  ends  to 


FOUNDRY-WOBK, 


67 


prevent  it  from  warping.    Tlie  two  parts  A  and 
with  the  moulding-boaids  C\  are  shown  in  front 
elevation  and  side  elevation  in  Fig.  51,  where  P 
and  Q  are  the  upper  and  lower  lugs. 

Set  one  half  of  the  flask  on  its  moulding-board, 
with  the  lugs  downward.  Sprinkle 
some  fine  sand  on  the  lower  part  of  the  ^^'^^'^ 

^  Moulding. 

flask,  through  a  sieve,  and  fill  up  the 
remainder  of  the  box  without  sifting,  but  press 
and  ram  the  sand  firmly  into  the  corners  of  the 
box  till  it  is  quite  full.  Scrape  oif  the  excess  with 
a  straight-edge,  sprinkle  a  little  loose  sand  on  the 
surface,  and  cover  it  with  another  board,  rubbing 
this  to  and  fro  till  it  fits  closely  on  the  edges  of 
the  box.  Now,  grasping  the  edges  of  both  boards 
in  the  hands,  turn  the  box  over  without  disturb- 
ing the  sand,  and  remove  the  upper  board. 
Sprinkle  the  moist  surface  of  the  sand  with  fine 
red  brick-dust  obtained  by  crushing  bricks.  Put 
the  dust  into  a  linen  bag,  and  sift  it  out  by  sha- 
king the  bag  while  holding  one  corner  of  the  open 
end  in  one  hand  and  a  corner  of  the  bottom  in  the 
other.  Blow  off  any  excess  of  dust,  and  lay  the 
pattern  on  the  sand  with  the  wider  face  down. 
Sprinkle  the  surface  of  the  pattern  w^ith  dust,  then 
set  the  upper  part  of  the  flask  in  place,  and  fill  it, 
and  cover  it  with  a  board  in  the  same  way  as  the 
first. 

The  upper  half  i^  now  to  be  removed,  so  that 


68 


FIRST  LESSONS  IN  METAL-WOBKING, 


tlie  pattern  may  be  taken  out.  Tap  the  top  board 
gently  all  over  with  a  light  mallet.  This  will 
loosen  the  sand  a  little  from  the  pattern,  and  the 
brick-dust  will  prevent  the  two  surfaces  of  the 
sand  fi'om  sticking  together.  Taking  hold  of  the 
upper  box  and  moulding-board  with  both  hands 
and  lifting  carefully  straight  upwards,  you  can 
remove  this  box  and  turn  it  over  on  its  moulding- 
board.  In  lifting,  you  must  be  careful  to  keep 
the  box  quite  level  and  uot  to  move  it  horizontal- 
ly, or  you  will  break  the  mould. 

If  the  sand  has  not  broken  away  to  any  consid- 
erable extent,  you  may  remove  the  pattern ;  but 
if  it  has,  the  breaks  must  first  be  repaired. 
Moisten  a  little  the  hollows  from  which  the  sand 
has  been  torn  out,  and  replace  the  other  box. 
The  pieces  torn  out  will  adhei^e  and  remain  in 
their  proper  places,  where  they  can  afterwards  be 
smoothed  off,  if  uecessaiy,  with  a  small  trowel. 
If  the  pattern  should  happen  to  come  off  with  the 
upper  flask,  it  can  be  removed  by  sticking  into  it, 
obliquely,  two  sharp-pointed  steel  wires,  tapping 
them  gently  sideways  and  endways  to  loosen  the 
pattern,  and  then  lifting  it  out  by  the  wires  as 
handles. 

In  one  end  of  the  flask  there  is  a  hole  through 
Avhich  the  melted  metal  is  to  be  poured  in.  Con- 
nect this  with  the  end  of  the  mould  by  a  small 
channel  cut  with  the  trowel,  and  smoothed  and 


FOUNDRY-WORK, 


69 


liardeiied  at  tlie  eutrauce  by  the  pressure  ot  the 
finger.  Repair  any  small  breaks,  blo^v  out  any 
loose  sand,  dust  both  surfaces  of  the  mould  lightly 
with  flour  or  with  finely  powdered  charcoal  in  the 
same  way  that  you  applied  the  brick-dust,  put  the 
two  halves  of  the  flask  together  and  clamp  them 
in  place,  and  everything  is  then  ready  for  the 
pouring  of  the  metal. 

Brass  is  best  melted  in  a  brass-founder's  furnace, 
which,  however,  it  is  not  necessary  to  describe 
here,  as  the  small  quantity  required  at  present  can 
be  melted  in  a  crucible  in  your  forge.  Make  a 
fire  of  good  hard  coke,  in  pieces  about  two  or 
three  inches  in  diameter.  Set  the  crucible  on  this, 
mouth  downwards,  urging  the  fire  gently  till  it  is 
thoroughly  heated,  because,  if  heated  first  on  the 
outside,  or  too  suddenly,  it  is  apt  to  crack.  When 
it  is  red  hot  all  over,  turn  it  over,  build  up  the 
fire  round  it  to  the  edge,  put  in  the  charge  of 
metal,  and  cover  it  with  large  pieces  of  coke. 
The  amount  of  metal  required  can  be  determined 
approximately  from  the  fact  that  the  density  of 
the  metal  is  14  or  15  times  that  of  the  wooden 
pattern.  To  allow  for  waste,  however,  and  to  be 
quite  sure  of  having  enough  to  fill  the  mould,  let 
the  weight  of  the  charge  be  from  20  to  25  times 
that  of  the  pattern.  Keep  up  a  strong  draught 
w^ith  the  bellows^  till  the  whole  of  the  charge  is 
melted. 


70  FIRST  LESSONS  IN  METAL- WOBKING. 


Brass  is  an  alloy  or  mixture  of  copper  and  zinc, 
usually  in  tlie  ratio  of  90  to  10.  When  it  is  ex- 
exposed  to  the  air  at  a  very  high  temperature,  the 
zinc  burns,  giving  off  a  light  blue  flame  and  a 
cloud  of  white  smoke.  For  thin  castings,  which 
chill  quickly,  and  which  therefore  require  a  high 
temperature,  the  metal  should  be  poured  in  this 
condition.  For  such  a  piece  as  the  one  in  this 
exercise,  a  somewhat  lower  temperature  will  be 
best,  such  as  is  unattended  by  the  flame  and  smoke. 
When  the  metal  has  cooled  to  this  point,  skim  off 
the  dross,  and  it  is  then  ready  to  be  poured. 

For  this  purpose,  after  having  turned  the  flask 
downward  to  let  any  loose  sand  that  might  pos- 
sibly have  fallen  into  the  mould  fall 
Exercise  24.  Upright,  with  the  mouth 

Casting  brass.  ^  .  i 

up,  and  m  such  a  way  that  the  point 
of  the  mould  at  wdiich  the  inlet  enters  shall  be  the 
highest  point,  otherwise  the  air  will  collect  at  any 
point  that  may  be  higher,  and  prevent  the  metal 
from  entering.  Pour  the  metal  carefully  into  the 
mould,  in  a  steady  stream  of  such  size  as  to  leave 
room  in  the  channel  or  "  ingate"  for  the  escape  of 
the  air  without  forming  bubbles,  which  might 
scatter  the  metal.  The  mould  must  be  filled  quite 
up  to  the  ingate,  to  insure  soundness  of  the  cast- 
ing at  the  top.  When  the  casting  is  "  set,"  the 
mould  is  opened,  the  piece  cooled,  the  ingate-piece 
sawn  off,  and  the  ridge  along  the  line  of  meeting 
of  the  halves  of  the  flask  filed  away. 


MANUFACTUBE  OF  WROUGHT-IRON.  71 


LESSON  XIL 

MANUFACTUKE  AND  PKOPERTIES  OF  WROUGHT-IEOIN^. 

We  have  seen  that  the  two  kinds  of  iron, 
called  No.  1  and  No.  2  foundry  pig,  are  used 
singly  or  mixed  in  various  pro23ortions  for  cast- 
iron,  and  No.  3^  or  forge-pig,  is  manufactured  into 
wrouirht-iron.  The  manufacture  consists  in  ex- 
pelling  the  other  substances,  mainly  carbon,  sili- 
con, phosphorus,  and  sulphur,  with  which  it  is 
mixed,  leaving  pure  iron. 

For  this  purpose,  the  iron  is  again  melted  in  a 
furnace  without  blast,  called  a  puddling-furnace," 
where  it  is  stirred  up  with  wrought-iron  rods  till 
nearly  all  the  carbon  has  been  burned  out  of  it 
by  contact  with  the  air,  and  the  other  impurities 
have  been  carried  away  in  a  slag,"  made  by 
throwing  limestone,  oxide  of  iron,  salt,  and  other 
fusible  substances  into  the  furnace.  It  thus  be- 
comes first  pasty  and  then  granular,  and  requires 
a  very  intense  heat  to  keep  it  from  solidifying. 
In  this  state  it  is  taken  out  of  the  furnace  in 
lumps  of  about  40  lbs.,  on  the  ends  of  the  iron 
rods,  and  hammered  by  heavy  hammers  driven 
by  machinery,  or  x3ompressed  between  powerful 
squeezers,"  the  remaining  silicon  and  other  im- 


72  FIRST  LESSONS  IN  METAL  WOEKING, 


purities  being  thus  pressed  out.  The  lump  of 
pure  iron  tlius  obtained  is  passed  between  strong 
cylindrical  rollers/  which  have  grooves  turned  in 


Fig.  52,  A. 

both,  opposite  each  other  as  in  Fig.  52,  and  thus 
drawn  out  into  bars  from  3  to  5  inches  wide,  and 


Fig.  52,  B. 

from  to  thick.  These  are  called  "muck- 
bars,"  or  puddled  bars,"  and  are  coarse  wTought- 
iron.  These  bars  are  cut  into  short  pieces,  which 
are  fastened  together,  reheated,  and  again  rolled 
out  to  such  sizes  and  shapes  as  may  be  required. 


MANUFACTURE  OF  WROUGHT-IROK  73 


The  iron  thus  produced  is  called  "  refined  "  iron. 
This  iron  is  sometimes  again  "piled"  and  reheated 
and  rolled,  producing  what  is  called  "double  re- 
fined" iron.  After  these  operations  the  iron  will 
be  found  to  have  an  entirely  different  structure 
from  that  of  cast-iron.  The  latter  is  composed  of 
granules  or  crystals.  Wrought-iron,  if  good,  has 
lost  its  granular  or  crystalline  structure,  each  of 
the  granules  having  been  drawn  out  into  a  long 
fibre,  so  that  the  bar  itself  is  a  bundle  of  such 
fibres  stuck  together  at  their  sides.  Wrought- 
iron  thus  resembles  a  piece  of  tough  wood,  while 
cast-iron  is  more  like  unstratified  stone,  such  as 
granite.  Cast-iron  has  the  same  structure  and 
strength  in  all  directions,  while  wrought-iron  is 
tougher  or  harder  to  tear  asundei*  by  a  force  ap- 
plied in  the  direction  of  the  length  of  the  fibres 
than  by  one  applied  perpendicular  to  this  direc- 
tion,— in  which  respect  again  it  is  analogous  to 
wood.    (Wood- working,  p.  17.) 

This  fibrous  structure  is  possessed  in  very  differ- 
ent degrees  by  different  kinds  of  wrought-iron.  An 
iron  of  poor  quality  can  be  readily  broken  across 
by  bending.  Take  a  piece  of  bar-iron  of  the 
cheaper  (and  therefore  poorer)  quality,  ^^^^.^jg^  25 
Nick  it  on  one  side  on  the  hardee.  Testing 
Lay  it  across  two  pieces  of       flat  wrought-iron 

.  T  p         •     1  I  J 1       on  the  anvil. 

iron  three  or  tour  mcnes  apart  on  the 

anvil,  the  nick  being  between  the  supports,  but 


74  FIRST  LESSONS  IN  METAL-WORKING. 


near  one  of  them,  and  strike  it  a  heavy  blow  or 
two  with  the  pene  of  a  hammer.  If  the  specimen 
is  of  veiy  poor  quality,  or  cold  short/'  it  will 
break  at  the  nick.  A  piece  of  better  quality 
will  stand  bending  cold  at  right  angles  without 
breaking;  and  a  very  tough  piece  may  be  bent 

double  without  breaking,  or 
will  split  at  the  nick,  as  in 
Fig.  53.  The  best  bar-iron 
can  be  tied  in  a  knot  cold, 
though  not  after  it  has  been 
nicked. 

Break  in  this  way  two  or  three  pieces  of  iron 
of  different  qualities.  Examine  the  surfaces  of 
the  fractures  with  a  lens.  You  find  that  the  bet- 
ter or  tougher  the  iron,  the  more  distinctly  fibrous 
it  is;  and  you  can  soon  learn  to  judge  of  the 
quality  of  wrought-iron,  as  of  cast-iron,  by  the 
appearance  of  a  freshly-broken  surface. 


1 


MANUFACTURE  AND  PROPERTIES  OF  STEEL.  75 


LESSON  XIIL 

MAIS^UFACTUEE  AKD  PROPEKTIES  OF  STEEL. 

You  have  learned  that  wrought-iron  is  nearly 
or  quite  pure  iron,  while  cast-iron  contains  from 
3  to  5,  or,  in  some  cases,  even  7  or  8  per  cent  of 
carbon.  Steel  is  intermediate  in  composition  be- 
tween these  two,  and  contains  from  1  per  cent  to 
0.15  of  one  per  cent  of  carbon.  It  might  be  sup- 
posed, therefore,  that  steel  could  be  made  in  the 
puddling-furnace  by  stopping  the  operation  be- 
fore the  carbon  is  all  removed;  and  this  process  is 
sometimes  actually  used.  It  is  difficult,  however, 
to  obtain  in  this  way  a  product  containing  exactly 
any  desired  proportion  of  carbon,  and  besides,  the 
distribution  of  the  carbon  throughout  the  mass  is 
apt  to  be  irregular,  or,  in  other  words,  the  steel  is 
not  homogeneous. 

For  a  long  while,  therefore,  steel  was  made  al- 
most exclusively  from  the  best  qualities  of 
wrought-iron  by  a  process  called  ^^cementation," 
a  process  which  is  still  in  use  for  the  manufacture 
of  fine  steel.    The  bars  of  wrought-iron  are  em- 


76 


FIRST  LESSONS  IN  METAL- WORKING. 


bedded  in  powdered  charcoal,  and  baked  in  a 
furnace  for  from  seven  to  fourteen  days  continu- 
ously. The  iron  is  then  found  to  have  increased 
in  weight  about  1^  per  cent  by  the  absorption  of 
carbon,  and  has  become  what  is  called  blistered" 
steel,  from  the  blisters  which  appear  on  its  sur- 
face, and  which  are  probably  caused  by  the  escape 
of  bubbles  of  air. 

From  the  blistered  steel  two  other  kinds  are 
made  called  "shear"  steel,  and  "cast"  or  "cruci- 
ble" steel.  The  former  is  made  by  fastening  to- 
gether a  number  of  bars  of  blistered  steel,  and 
hammering  them  at  a  welding  heat  with  a  trip- 
hammer. The  process  is  like  that  of  refining 
wrought-iron,  and  has  a  similar  effect — the  pro- 
duction of  a  more  or  less  fibrous  structure.  The 
steel  thus  made  is  especially  adapted  for  welding 
to  wrought-iron,  and  is  commonly  used  in  making 
the  cutting  edges  of  those  tools  of  whick  the 
other  parts  are  made  of  iron.  The  other  kind  of 
steel  is  made  by  melting  in  crucibles  bars  of  blis- 
tered steel,  broken  for  the  purpose  into  conven- 
ient fragments.  This  is  harder  to  weld  than 
shear-steel,  and  is  used  principally  for  objects 
which  are  entirely  of  steel,  and  which  are  cast  in 
the  shape  required,  although  it  can  also  be 
welded,  with  proper  precautions. 

As  long  as  steel  was  manufactured  only  by  the 
methods  just  described,  only  a   small  quantity 


MANUFACTURE  AND  PR0PEBTIE8  OF  STEEL.  77 


could  be  produced  at  once,  and  it  was  therefore 
very  expensive.  When  large  works  are  to  be 
made  of  crucible  steel,  it  is  necessary  to  have 
great  numbers  of  crucibles  ready  at  the  same  time 
for  pouring,  and  very  great  care  is  necessary  to 
make  sure  that  the  charges  of  all  the  crucibles 
shall  have  exactly  the  same  qualities.  With  such 
precautions,  however,  very  large  works,  such  even 
as  cannons  weighing  139  tons,  are  satisfactorily 
cast  at  the  great  Krnpp  foundry  in  Germany. 

In  recent  times  much  less  expensive  processes 
have  been  devised  for  making  steel  in  very  large 
quantities.  These  are  known  as  the  Bessemer 
process  and  the  Siemens-Martin  process.  They 
need  not  be  described  at  present.  They  are  used 
mainly  in  the  production  of  very  large  pieces,  such 
as  are  used  in  the  construction  of  heavy  machinery, 
bridges,  railroad  tracks,  steel  ships  and  cannon, 
and  the  armor-plating  of  war-vessels.  For  small 
tools,  shear-steel  and  crucible-steel  are  still  gener- 
ally employed. 

To  the  mechanic  who  is  working  in  steel,  the 
properties  of  the  metal  are  generally  more  impor- 
tant than  the  way  in  which  it  may  have  been 
manufactured  ;  and  in  whatever  way  his  steel  may 
have  been  made,  he  distinguishes  what  he  calls 
"  high-grade''  or  tool "  steel  from  low-grade," 
mild,"  or     machineiy"  steel.    The  former  con- 


78 


FIRST  LESSONS  IN  METAL^WORKING. 


tains  about  1  per  cent  of  carbon,  the  latter  from 
1  to  1  as  much. 

On  your  anvil  are  two  specimens  of  square 
steel,  each  18''  long.  One  is  of  high  grade,  the 
other  of  mild  steel.  Study  the  properties  of  each. 
First,  heating  them  to  redness,  nick  them  both  on 
the  hardee,  8^'_  from  the  end;  and  then,  after  cool- 
ing them  slowly,  try  to  break  them  as  you  did 
Exercise  26.  ^^'^^^      Exercisc  26.    Or  better, 

Testing  steel  lay  the  piccc  across  the  hole  in  your 
on  the  anvil,    ^^^-j^  |^^|^  ^  uarrow  fuller  on  the  nick, 

and  let  a  helper  strike  with  a  sledge  till  the  piece 
breaks.  Compare  the  effort  necessary  to  bi*eak 
each  of  these  with  that  required  to  break  a  piece 
of  bar-iron  similarly  treated.  Examine  the  frac- 
tures  and  compare  them  with  each  other,  and  with 
that  of  good  wrought-iron.  Make  memoranda  of 
the  results  of  all  your  observations. 

Next,  wedge  the  short  pieces  one  after  the 
other  in  the  hole  of  the  anvil,  making,  if  neces- 
sary, a  wrought-iron  wedge  to  hold  the  piece 
tightly  in  position,  about  2''  of  the  piece  being  in 
the  hole.  Strike  the  piece  sideways  near  the  upper 
end,  till  it  is  bent  aside  at  an  angle  of  50°  or  60°. 
Strike  it  on  the  other  side  and  bend  it  back  to  an 
equal  extent  in  the  other  direction.  Try  to  break 
it  by  repeated  bendings,  and  note  how^  much  of 
such  treatment  each  piece  will  stand.  Cut  a  simi- 


MANUFACTURE  AND  PROPERTIES  OF  STEEL.  79 


lar  piece  of  bar-iron,  and  compare  this  with  the 
two  kinds  of  steel. 

Next,  heat  one  end  of  each  piece  to  a  cherry-red, 
plunge  it  quickly  into  water,  and  hold  it  there  till 
cold.  With  an  old  file  try  the  hard-  Exercise  27. 
ness  of  the  end  thus  treated,  and  com-  Experiments 
pare  with  that  of  the  opposite  ends,  hardening. 
You  find  that  sudden  cooling  from  a  red  heat 
liardens  tool-steel.  You  have  long  ago  found  that 
no  such  effect  is  produced  on  wrought-iron ;  and 
you  find  that  mild  steel  is  in  this  respect  much 
like  wrought-iron. 

Again,  test  the  piece  thus  hai'dened  for  tough- 
ness, as  you  did  before  hardening  it:  you  find  it 
has  become  not  only  hard,  but  brittle. 

Lastly,  heat  about  2''  of  one  end  of  the  tool- 
steel  to  whiteness,  and  treat  it  as  you  did 
wrought-iron,  in  previous  exercises  for  drawing 
and  pointing.  You  find  it  brittle,  like  hot-short 
iron,  and  it  is  evident  that  it  cannot  be  worked 
at  such  a  heat.  Try  successively  lower  tempera- 
tures, till  you  find  one  at  which  it  can  be  forged. 
Do  the  same  with  the  low  steel.  You  will  find 
hereafter  that  though  the  steel  is  not  made  brittle 
at  this  temperature,  it  has  probably  suffered  an- 
other injury,  which  you  will  understand  Avhen  you 
come  to  consider  the  subject  of  ^^lardening"  and 
^'tempering"  steel,  that  it  is  necessary  to  work  it 
at  a  still  lower  temperature,  and  that  each  kind 
of  steel  has  a  temperature  of  its  own  at  which  it 


80  FIRST  LESSONS  IN  METAL- WORKING, 


can  be  worked,  and  which,  generally,  can  be  as- 
certained only  by  trial. 

Collect,  now,  all  the  points  of  resemblance  and 
of  difference  that  you  have  discovered  between 
wrought-iron,  cast-iron,  mild  steel,  and  high-grade 
steel,  and  write  them  out  in  a  clear  and  orderly 
manner  in  your  memorandum-book. 


WELDING  STEEL:  LOW  GRADE, 


81 


LESSON  XIV. 

WELDIIN^G  STEEL  \   LOW  GRADE. 

We  Avill  make  our  first  attempt  at  a  steel  weld 
witli  a  low-grade  steel  containing  about  ^  of  1  per 
cent  of  carbon.  This  may  be  either  a  mild  shear- 
steel,  or  a  Bessemer  steel  of  about  the  quality  now 
used  for  carriage-tires.  It  will  differ  but  little 
from  wrouglit-iron,  except  that  it  will  be  tougher. 
It  will  be  easier  to  weld  than  tool-steel,  but  will 
require  more  care  than  wrought-iron.  We  will 
take  the  tough  6''  piece  of  the  last  exercise,  and 
join  it  again  to  the  piece  from  which  it  was  cut. 

First,  straighten  the  pieces  at  a  dull-red  heat. 
Upset  and  scarf  one  end  of  each  piece,  with  the 
aid  of  a  helper,  using  a  fuller,  and  proceeding  as 
in  Exercise  19.  Be  careful  to  use  a  coke  fire  in- 
stead of  one  of  green  coal,  and  to  work  at  a  low 
heat,  never  exceeding  a  cherry-red.  Unless  you 
work  very  expeditiously,  therefore,  striking  always 
at  exactly  the  right  place,  and  without  loss  of 
time,  you  Avill  not  be  able  to  prepare  the  scarf- 
piece  in  one  heat.    Reheat  cautiously,  „  . 

^       .  .        ,        .  ,  Exercise  28. 

moving  and  turning  the  piece  occasion-  weiding  steel 
ally  in  the  fire,  and  watching  the  color  on  steel;  low 
closely.    Keep  the  other  piece  in  the 
edge  of  the  fire,  so  that  it  shall  be  nearly  ready 


82  FIRST  LESSONS  IN  METAL- WORKING. 


for  use  when  wanted,  but  in  no  danger  of  burning. 
Make  the  scarf  in  as  few  heats  as  possible.  When 
the  two  surfaces  are  prepared,  put  the  pieces  in  the 
fire  side  by  side,  as  in  Exercise  19,  and  raise  them 
slowly  to  a  cherry-red.  Sprinkle  the  scarf -surf aces 
witli  powdered  borax  and  allow  it  to  melt,  and 
spread  over  the  surface  before  you  put  the  pieces 
into  the  fire  again.  Heat  them  slowly,  and  as 
soon  as  the  borax  smokes,  which  will  be  an  indi- 
cation that  they  have  reached  a  cherry-red,  with- 
draw them  from  the  fire,  and  finish  the  weld  as  in 
Exercise  19,  observing  all  the  precautions  there 
described,  but  remembering  that,  after  the  first 
adhesion  of  the  two  surfaces,  there  is  not  the  same 
necessity  for  rapid  work  in  this  case  as  in  the 
iron  weld,  because  the  steel,  being  Avorked  at  a 
lower  temperature,  does  not  quite  so  quickly  fall 
below  the  required  heat.  Remember  that,  in  this 
case  as  in  the  previous  ones,  it  is  essential  to  a 
good  weld  that  you  should  have  a  bright,  clean, 
and  deep  fire;  but  you  should  not  have  a  broad 
one,  as  that  will  heat  too  much  of  the  length  of 
the  pieces.  Finish  square,  straight,  and  smooth, 
as  in  similar  work  with  wrought-iron,  and  test  in 
the  same  w^ay.  If  the  result  is  not  satisfactory, 
cut  out  the  weld  on  the  hardee  at  a  red  heat,  and 
repeat. 

Try  next  a  split  weld,  of  steel  on  iron,  taking 
one  end  of  the  piece  just  finished,  and  an  8^^  piece 


WELDING  STEEL:  LOW-GRADE. 


83 


of  V  square  bar-iron.  Make  this  weld  without  a 
helper.  Upset  and  split  the  iroUj  and  Exercise  29. 
lay  it  ill  the  edge  of  the  fire  to  keep  it  Welding  mild 
at  a  red  heat  while  you  are  preparing  °" 
the  steel  wedge-piece.  This  is  because  the  steel 
must  be  worked  at  a  lower  temperature  than  the 
iron,  and  therefore,  when  they  are  presently  put 
into  the  fire  together,  the  iron  should  be  hot  and 
the  steel  cold,  so  that  they  may  reach  their  proper 
heats  at  the  same  time.  Hammer  the  steel  to  the 
wedge-shape,  and  fit  the  hot  V-piece  to  it  as  in 
Exercise  19.  Then,  without  letting  the  V-piece 
cool,  place  both  together  in  a  good  welding  fire 
and  raise  the  steel  to  a  bright  cherry-heat,  when 
the  iron  will  probably  be  at  a  welding  heat. 
During  this  operation  keep  them  on  the  top  of 
the  fire,  so  that  they  can  be  easily  watched,  and 
move  them  about  so  that  they  shall  not  get  too 
hot  beyond  the  joint.  In  doing  this,  take  hold  of 
both  pieces,  and  keep  the  wedge  pressed  well  up 
into  the  split.  When  the  joint  is  at  the  proper 
heat,  take  up  some  powdered  borax  on  a  bit  of 
hoop-iron  or  small  flattened  bar-iron  as  a  sort  of 
spoon,  and  spiinkle  it  abundantly  on  the  joint. 
Watch  the  melting  of  this,  while  you  keep  up  the 
heat  by  means  of  the  blast.  When  it  has  thor- 
oughly run  into  and  around  the  joint,  and  the 
steel  is  at  a  bright  cherry-red,  take  hold  of  the 
joint  with  a  pair  of  tongs  while  it  lies  in  the  fire. 


84  FIRST  LESSONS  IN  METAL- WORKING, 

and  without  removing  it,  squeeze  it  vigorously. 
This  will  partially  weld  the  joint,  and  enable  you 
to  handle  the  pieces  with  less  risk  of  separating 
them.  Remove  them  to  the  anvil,  strike  a  few 
quick  blows  to  make  good  the  weld,  and  you  can 
then  finish  more  at  your  leisure,  reheating  the 
pieces  as  often  as  may  be  necessary.  The  finish- 
ing and  testing  should  be  exactly  as  in  Ex.  19. 


WELDING  STEEL:  HIGH-GRADE.  85 


LESSON  XV. 

WELDII^G  STEEL  :  HIGH-GRADE. 

We  will  now  try  a"  weld  of  liigh-grade  or  tool 
steely  which  will  be  somewhat  more  difficult  to 
mana2:e.    Take  the  piece  of  V'  tool  „  . 

^  r  ^  Exercise  30. 

steel  of  Ex.  26.  Be  careful  to  per-  Weiding  high- 
form  all  operations  on  it  at  a  tempera-  s^^^®  ^^^^^ 

.  steel. 

ture  lower  than  that  at  which  you  have 
found  that  it  becomes  brittle.  Upset  it  as  in  the  last 
exercise,  holding  the  piece  this  time  in  the  vise  for 
the  purpose.  In  upsetting  in  the  vise  it  is  easier 
to  prevent  bending,  if  you  are  careful  not  to  strike 
too  hard.  On  the  other  hand,  if  you  set  the 
piece  too  low  in  the  vise  you  will  limit  the  upset- 
tin  o;  to  the  extreme  end,  and  the  work  will  turn 
out  too  thin  when  the  weld  is  finished.  While 
upsetting,  keep  the  piece  square  and  straight  by 
occasional  hammering  on  the  anvil.  With  this 
kind  of  steel  you  will  probably  have  to  reheat 
each  piece  several  times  for  each  operation,  which 
will  do  no  harm  unless  you  make  it  too  hot. 
When  it  is  properly  upset,  split  it,  again  at  a  red 


86 


FIRST  LESSONS  IN  METAL-WORKING. 


heat,  holding  it  upright  in  the  vise  and  using  a 
thin  hot-chisel.  When  the  cut  has  been  made  to 
the  proper  depth,  widen  it  a  little  with  a  duller 
chisel,  spread  the  lips,  form  the  wedge-piece,  and 
drive  it  in  till  it  reaches  quite  to  the  bottom  of 
the  cut,  all  as  in  previous  exercises  of  the  same 
kind.  Put  the  pieces  together  and  fit  them  as 
closely  as  you  can,  at  a  red  heat.  They  are  now 
to  be  heated  together  in  the  fire,  with  even  more 
caution  than  in  the  last  exercise  as  to  the  charac- 
ter of  the  fire,  the  moving  about  in  the  fire  to  heat 
all  parts  of  the  joint  but  without  parting  the 
pieces,  and  the  keeping  within  proper  limits  of 
temperature.  Sprinkle  abundantly  with  borax 
without  removing  from  the  fire,  pinch  together  in 
the  fire,  and  weld  and  finish,  all  as  in  the  last  ex- 
ercise. 

This  will  probably  be  found  to  be  a  rather  dif- 
ficult task,  and  you  may  have  to  try  several  times 
before  succeeding.  Some  of  the  causes  of  failure 
are  the  following  : 

1°.  Overheating  at  any  stage  of  the  operation, 
which  will  cause  the  steel  to  break  or  crumble 
under  the  hammer. 

2°.  Underheating  at  the  time  of  welding, 
which  will  prevent  the  pieces  from  uniting. 

3°.  Dirty  fire,  letting  cinders  get  into  the  joint. 

4°.  Too  much  thinning  of  the  lips  of  the  V- 
piece,  which  will  make  the  joint  so  weak  that  it 


WELDING  STEEL:  HIGH-GRADE. 


87 


may  be  impossible  to  keep  the  two  pieces  together 
in  the  fire,  or  while  removing  them  to  the  anvil. 

5°.  Too  short  a  notch,  leaving  part  of  the 
thinned  wedge  exposed. 

6°.  Loss  of  time  in  striking,  after  removing  the 
work  from  the  fire. 

7°.  Imperfect  contact  of  the  edge  of  the  wedge 
with  the  bottom  of  the  notch,  leaving  a  hole,  or, 
if  this  is  closed  by  hammering,  leaving  the  piece 
too  thin. 

8°.  Imperfect  union  of  the  edges  of  the  lips  of 
the  V-piece  with  the  sides  of  the  wedge,  owing 
to  burning  of  the  edges,  which  often  happens  if 
they  are  too  thin. 


88 


FIMST  LESSONS  IN  METAL- WORKING, 


LESSON  XVI. 

HAEDElSriNG  AIN^D  TEMPERIIN^G  STEEL. 

You  have  learned  (Lesson  XIII.,  p.  79)  that 
high-grade  steel,  when  cooled  from  a  red  heat  by 
plunging  into  water,  becomes  very  hard.  The 
same  effect,  with  some  differences  in  degree  which 
need  not  be  considered  yet,  results  when  the  steel 
is  cooled  suddenly  from  the  same  temperature  in 
any  other  way,  as  by  plunging  into  oil  or  tallow, 
or  even,  if  it  is  a  thin  piece,  by  contact  with  a 
large  mass  of  cold  metal,  such  as  the  anvil.  Again, 
you  have  found  that  the  piece  which  has  been 
thus  hardened  has  also  been  made  brittle.  In 
some  tools,  as  in  those  intended  for  cutting  metals 
and  stone,  this  property  of  hardness  is  of  great 
value  ;  but  on  the  other  hand,  the  brittleness  which 
accompanies  it  may  very  much  lessen  this  value. 
The  sharp  corner  of  a  scrap  of  glass,  for  instance, 
is  hard  enough  to  scratch  iron  or  steel ;  but  the 
brittleness  of  glass  makes  it  worthless  as  a  mate- 
rial for  cutting-tools,  as  its  sharp  edge  is  quickly 
broken  off*.  The  same  is  true  of  very  hard  steel. 
It  is  important,  therefore,  to  understand  exactly 


\ 

HABDENING  AND  TEMPERING  STEEL.  89 

the  means  by  which  this  hardness  is  produced,  and 
the  means  by  which  the  brittleness  can  be  dimin- 
ished without  sacrificing  too  much  of  the  hardness. 

In  the  first  place,  the  amount  of  hardness  pro- 
duced by  sudden  cooling  depends  on  the  tempera- 
ture from  which  the  cooling  takes  place.  Perform 
the  following  experiment  to  satisfy  yourself  of 
this.  Take  four  pieces  of  high-grade  octagon  or 
round  tool-steel,  \"  or  f^^in  diameter  and  2''  long. 
Mark  them,  near  one  end,  with  file-scratches,  so 
that  you  can  identify  them.  Let  them  lie  for  five 
minutes,  one  in  boiling  water,  one  in  boiling  lin- 
seed-oil, one  in  red-hot  melted  lead,  and  one  in  the 
fire  till  it  is  as  hot  as  it  can  be  made  without  bui*n- 
ing.  (The  oil  may  be  boiled  in  a  small  iron  ladle 
on  a  dull  forge-fire  with  a  very  gentle  blast,  taking 
care  not  to  let  it  boil  over,  and,  if  it  takes  fire, 
raising  it  from  the  fire  and  letting  it  cool  a  little, 
so  that  you  can  blow  it  out,  but  without  removing 
it  from  the  forge,  for  fear  of  accident.  The  lead 
may  be  melted  in  a  similar  ladle,  or  in  the  same 
one  after  the  oil  has  been  poured  off  and  the  rem- 
nant of  it  burned  out.  The  lead  must  be  red- 
hot.)  The  first  of  the  four  pieces  will  then  be  at 
a  temperature  of  212°  F.,  the  second  at  about  580'', 
the  third  at  about  1500°,  and  the  fourth  at  about 
2500''.  Picking  up  each  piece  with  a  small  pair 
of  tongs  which  have  been  standing  in  the  fluid  or 
the  fire  so  that  their  Jaws  are  at  the  same  temper- 


90  FIRST  LESSONS  IN  METAL-WOIiKING, 


ature  as  the  piece  of  steel  and  will  not  chill  it, 
drop  each  into  cold  water. 

Test  them,  as  to  hardness,  in  the  following  way: 
Clamp  the  piece  in  a  hand-vise,  as  in  Fig.  54,  let- 
ting it  project  about      at  the  side  of 
the  vise.    Fasten  the  hand-vise  to  a 
piece  of  wood  four  or  five  feet  long 
and        wide,  with  a 
screw  and  washer,  as  in 
the  same  figure.  Sup- 
porting one  end  of  the 
Fig.  54.  strip   on  a  bench  or 

table,  and  preventing  it  from  shifting  by  means 
of  a  nail  passing  through  an  auger-hole,  let  the 


Exercise  31. 
Experiment 
on  hardening 
steel. 


Fig.  55. 

end  of  the  piece  of  steel  rest  on  the  grindstone 
Hang  a  weight  of  8  or  10  lbs.  on  the  strip,  to  pro- 
duce a  suitable  pressure  on  the  stone,  making  a 
notch  for  the  cord  so  that  it  shall  be  attached  at 
the  same  place  in  all  the  experiments.    Let  the 


HARDENING  AND  TEMPERING  STEEL.  91 


piece  bear  on  the  stone,  keeping  it  well  watered, 
and  grind  the  end  square,  moving  it  to  and  fro 
sideways,  so  as  not  to  wear  the  stone  in  one  place. 
When  all  the  ends  are  square,  weigh  the  pieces, 
and  record  the  weight  of  each.  Then  grind  off 
from  each  as  much  as  the  stone  will  remove  in 
1000  or  1500  revolutions,  and  weigh  the  pieces 
again.  The  percentage  of  loss  of  weight  will  in- 
dicate the  softness  of  the  pieces,  since  all  have 
been  treated  alike.  You  can  therefore  arrange 
the  pieces  in  the  order  of  hardness,  and  can  learn 
the  effect  of  sudden  cooling  from  these  tempera- 
tures. 

Next,  holding  the  pieces  in  succession  on  the 
anvil,  and  striking  them  at  the  end  with  the  ham- 
mer, first  gently,  and  then  more  forcibly,  you  can 
learn,  in  a  general  way,  which  are  the  most  brit- 
tle, though  this  experiment  is  only  a  rough  one, 
and  its  results  cannot  be  expressed  in  figures. 
Make  a  record  of  these  results,  and  remember 
them. 

The  hardness  produced  by  sudden  cooling  from 
a  red  heat  can  be  entirely  removed  by  cooling  the 
metal  slowly  from  a  red  heat ;  and  the  more 
slowly  it  is  cooled,  the  softer  and  touo;her  will  the 
steel  be.  The  brittleness  and  the  hardness  are 
reduced  togethero  Experiment  on  this  in  the 
followmg  way :  Heat  three  pieces  of  steel,  such  as 
you  used  in  the  last  experiment,  to  a  bright  red 


92 


FIRST  LESSONS  IN  METAL-WORKING. 


heat  in  melted  lead,  having,  as  before,  marked 
.  them  for  identification.   Harden  them 

Exercise  32.  i 

Experiment  all  alike,  by  plunging  them  suddenly 
on  annealing  ^j^to  cold  Water.  Then,  heating  them 
^    ■  to  a  bright  red  again,  cool  them  in  the 

following  ways : 

No.  1,  by  holding  it  in  the  tongs  (previously 
heated  to  a  black  red")  and  letting  it  cool  in 
the  air  till  the  redness  is  invisible  in  the  light, 
but  Just  visible  in  a  dark  corner,  and  then  plung- 
ing it  into  water. 

No.  2,  by  laying  it  on  the  loose  cinders  in  the 
forge,  and  letting  it  cool  slowly  in  the  air ;  and. 

No.  3,  by  leaving  it,  red-hot  (but  not  white-hot), 
in  the  fire,  well  covered  with  the  coals  and  cin- 
ders, letting  the  fire  go  out,  and  leaving  it  there 
till  quite  cold. 

Test  these  pieces  for  hardness  and  brittleness, 
as  in  the  last  experiment.  You  will  find  that  the 
steel  has  recovered  more  or  less  of  its  toughness, 
and  also  of  its  softness,  by  this  gradual  cooling. 
This  process  is  called  annealing;  and  the  three 
methods  you  have  Just  tried  are  called  water,  air, 
and  fire  annealing.  Make  a  record  of  the  effects 
of  each,  and  remember  them. 

It  is  usually  said  that  while  cooling  suddenly 
from  a  red-heat  hardens  steel,  cooling  from  a 
lower  heat,  whether  slowly  (as  in  the  air)  or 
quickly  (as  in  No.  1  of  your  last  experiments), 


HARDENim  AND  TEMPERING  STEEL. 


93 


softens  it.  Try  to  ascertain  from  your  experi- 
ments wlietlier  these  statements  are  cori'ect. 

Glass  is  very  mucli  like  steel  in  the  effects  of 
heat  on  it,  while  some  metals  and  alloys,  as  cop- 
per and  brass,  behave,  as  yon  can  now  easily 
prove  by  experiment,  in  exactly  the  opposite  way, 
being  hardened  by  slow  cooling  and  softened  by 
rapid  cooling. 

Yon  have  found  now  that,  in  general,  the  harder 
steel  is,  the  more  brittle  it  is,  and  the  tougher  the 
softer.  It  is  therefore  impossible  to  retain  the 
highest  degree  of  hardness  with  great  tough- 
ness; and  for  each  particular  use  to  which  steel 
is  to  be  put  we  have  to  try  to  secure  the  particu- 
lar degree  of  hardness  and  toughness  most  nearly 
suited  to  that  nse. 

As  your  experiments  show  that  the  hardness 
and  toughness  of  steel  depend  on  the  temperature 
from  which  the  metal  is  cooled,  and  as  small  dif- 
ferences in  toughness  may  suffice  to  make  a  tool 
very  valuable  or  altogether  useless  for  a  given  pur- 
pose, it  is  important  to  know  how  to  select  the 
right  temperature  for  each  case.  The  red  which 
is  Just  visible  in  the  dark  (or  black-red,  as  it  is 
called)  is  a  very  good  indication  of  one  tempera- 
ture—about 500°  to  525"  C,  or  932°  to  977°  F. ; 
but  sudden  cooling  from  this  point  gives  a  hard- 
ness which,  though  it  serves  very  well  for  files,  is 
too  great  for  most  other  tools.    If  a  tool  which 


94  FIRST  LESSOiSfS  IN  METAL-  WORKING. 


has  been  thus  hardened  too  much  be  raised  again 
to  some  lower  temperature,  and  then  cooled  from 
that  temperature,  it  will  be  softer  than  before ; 
and  by  selecting  the  proper  temperature  it  will  be 
possible  to  give  it  any  lower  degree  of  hardness 
that  may  be  required.  This  process  is  called 
^'letting  down"  or  ^Hempering."  Success  in  tem- 
pering depends — 

First,  on  the  selection  of  the  proper  tempera- 
ture; 

Second,  on  the  method  of  applying  the  heat; 
and. 

Third,  on  the  method  of  cooling. 
We  will  consider  these  three  subjects  sepa- 
rately : 

1.  The  temperature  used,  when  it  is  lower  than 
the  black-red  heat,  is  indicated  by  the  color  which 
is  assumed  by  a  brightened  portion  of  the  surface 
of  the  steel.  Iron  or  steel  when  heated  in  the 
air  oxidizes  on  the  surface.  Grind  two  or  three 
inches  of  the  surface  of  an  old  flat  file,  making  it 
bright  on  one  side.  Heat  a  piece  of  V  bar-iron, 
15'^  or  20''  lonp;,  to  a  bris:ht  red  at  one 

Exercise  33.  ^         .        ^  . 

Experiment  ^^d,  and  lay  the  piece  of  brightened 
on  colors  of  g^^el  ou  it,  in  a  good  light,  with  the 

heated  steel  •  •  • 

bright  part  projecting  about  an  inch  or 
two  beyond  the  end  of  the  hot  bar.  The  project- 
ing part  will  be  cooler  than  the  rest,  and  the  heat 
will  travel  along  to  it  gradually.    Fix  your  atten- 


HAEDEmm  AND  TEMPEBlNG  STEEL.  95 


tion  on  the  end,  and  watch  and  record  the  several 
colors  as  they  appear  there,  one  after  the  other. 
These  colors  a-re  produced  in  the  same  way  as  the 
colors  of  the  soap-bubble,  and,  like  them,  they 
change  with  the  thickness  of  the  very  thin  film 
which  causes  them.  As  the  temperature  of  the 
steel  rises  the  thickness  of  the  film  of  oxide  of  iron 
increases,  and  the  color  changes.  The  color  is 
therefore  an  indication  of  the  thickness  of  the 
film,  and  that  in  its  turn  shows  the  temperature 
of  the  metal.  It  has  been  found  that  the  tem- 
peratui-es  corresponding  to  the  several  colors  are 


as  follows :  ^ 

1.  Very  pale  yellow,  .    .    .  221°  C.  or  430°  F. 

2.  Pale  straw,   232  "  450 

3.  Full  yellow,  .....  243  "  470 

4.  Brown,     ......  254  "  490 

5.  Brown,  with  purple  spots,  265  ^'  510 

6.  Purple,   277  "  530 

7.  Bright  blue,   288  "  550 

8.  Full  blue,   293  "  560 

9.  Dark  blue,   316  "  600 


If  a  piece  of  steel  whicli  has  been  hardened  be 
heated  to  one  of  these  colors  and  then  cooled,  it 
will  be  softened,  and  the  highier  the  temperature 
to  whicli  it  has  been  raised  the  softer  it  will  be. 
Try  this  in  the  following  way :  Take  three  pieces 


*  Percy's  Metallurgy. 


96 


FIRST  LESSONS  IN  METAL-  WORKING. 


of  octagon  steel,  as  in  your  last  experiments,  and 
harden  them  by  plunging  them  in  water  at  a  red 
.    ^     heat.    Rub  them  on  a  piece  of  sjrind- 

Exercise  34.  ^  i    •  i 

Bxperiment  stone  or  other  sandstone  to  brighten 
on  tempering  them.  Lay  them  on  a  red-hot  bar  of 
iron  supported  over  a  vessel  of  water. 
When  any  one  of  the  pieces  shows  a  pale-straw 
color,  push  it  off  into  the  water.  Do  the  same 
with  the  others  when  they  reach  a  light  purple 
and  a  dark  blue  respectively.  Now,  using  an  old 
tile,  try  how  much  of  each  piece  you  can  remove 
by  a  given  number,  say  fifty,  of  similar  strokes  of 
the  file,  and  thus  compare  the  results  obtained  by 
tempering  from  these  various  temperatures.  You 
might  measure  the  hardness  on  the  grindstone, 
but  it  is  well  also  to  get  accustomed  to  Judging 
the  hardness  approximately  by  the  way  the  metal 
feels  under  the  file. 

It  is  generally  stated  that  the  colors  in  the  pre- 
ceding table  indicate  the  proper  temperatures  for 
the  following  objects,  respectively  :^ 

No.  1.  Lancets. 

2.  Razors  and  surgical  instruments. 

3.  Penknives. 

4.  Small  shears,  chisels  for  cold  iron. 

5.  Axes,  planes,  pocket-knives. 

6.  Table-knives,  large  shears. 


Percy's  Metallurgy. 


HARDENim  AND  TEMPERING  STEEL.  97 


7.  Swords^  springs. 

8.  Fine  saws,  daggers,  augers. 

9.  Saws. 

As  your  future  exercises  give  you  opportunity, 
you  ought  to  compare  these  results  with  those  of 
your  own  experience,  remembering  the  agree- 
ments, and  the  differences  if  you  find  any,  and 
noticing  any  peculiarities  in  the  behavior  of  differ- 
ent kinds  of  steel,  so  as  to  know  how  to  treat  dif- 
ferent kinds  when  particular  results  are  sought. 

The  three  pieces  tempered  in  the  last  experi- 
ment may  be  tested  also  as  to  toughness,  by  hold- 
ing them  one  after  the  other  in  exactly  the  same 
way  in  a  vise,  and  striking  them  on  one  side  in- 
creasingly heavy  blows  with  the  hammer  till  you 
break  them.  No  very  exact  result  will  be  reached 
in  this  way,  because  you  cannot  measure  the 
enei'gy  of  your  blows ;  but  you  can  form  an  ap- 
proximate estimate  of  the  toughness  of  the  pieces. 


98  FIRST  LESSONS  IN  METAL-  WOBKINO. 


LESSON  XYIL 

HARDElSrmG  AND  TEMPERING  ^T^ML— Continued. 

We  come  now  to  consider — 

2.  The  method  of  applying  heat. 

When  a  piece  is  to  be  hardened  all  over  alike, 
it  is  important  that  it  should  have  the  same  tem- 
perature throughout.  It  may,  if  not  too  small, 
be  heated  in  the  forge-fire ;  but  it  must  be  moved 
about,  so  that  all  parts  may  be  exposed  to  the 
heat,  and  must  be  heated  slowly,  so  that  all  may 
have  time  to  arrive  at  the  same  temperature. 

The  hollow  fire  is  useful  for  this  purpose,  as  it 
allows  the  piece  to  be  watched  closely,  and  in- 
sures the  heating  of  the  top  as  well  as  the  bottom. 
If  the  piece  is  small,  an  excellent  plan  is  to  im- 
merse it  for  some  minutes  in  red-hot  melted  lead. 
The  piece  quickly  takes  the  temperature  of  the 
lead,  and  care  must  therefore  be  taken  not  to 
allow  the  latter  to  rise  to  the  point  at  which 
it  would  injure  the  steel.  The  lead  must  be 
watched,  and  if  it  is  found  to  be  getting  too  hot, 
it  must  be  cooled  by  putting  the  end  of  a  bar  of 


HABDENING  AND  TEMPERING  STEEL.  99 


cold  iron  into  it.  Tlie  pieces  should  be  rubbed 
with  soft  soap  before  immersing  them,  to  prevent 
the  lead  from  sticking;  or  a  paste  made  of  black- 
lead  and  water  may  be  used  ;  but  in  this  case 
care  must  be  taken  to  let  the  paste  dry  before  im- 
mersing the  piece,  as  otherwise  the  steam  produced 
may  scatter  the  lead  in  a  dangerous  way. 

If  small  objects  be  removed  from  the  lead  with 
cold  tongs,  they  will  be  irregulai-ly  cooled.  It 
will  be  well  therefore  to  let  the  ends  of  the  tongs 
lie  in  the  lead  for  some  time ;  or  they  may  be 
first  heated  in  the  fire,  and  then  stood  in  the 
lead  till  wanted;  or  the  piece  may  be  held  by 
means  of  a  piece  of  soft  wire  twisted  round  it  as  a 
handle. 

The  heat  for  annealing  may  be  applied  in  the 
same  way  as  that  for  hardening.  The  heat  for 
tempering  would  be  more  difficult  to  manage  if  it 
were  always  necessary  that  all  parts  of  the  piece 
should  have  the  same  temperature^  because  all 
will  not  reach  this  temperatm'e,  or  show  the  cor- 
responding color  at  the  same  time.  Fortunately, 
however,  this  is  seldom  required.  It  is  always, 
for  instance,  the  edge  of  a  cutting-tool  that  is  to  be 
tempered ;  the  exact  condition  of  the  rest  of  the 
tool  is  not  so  important.  It  is  the  face  of  a  ham- 
mer, the  point  of  a  drill,  the  upper  surface  of  an 
anvil,  that  is  to  be  tempered,  and  it  is  on  these 
that  the  attention  is  to  be  fixed  while  the  piece  is 


100         FIRST  LESSON'S  IN  METAL-WORKING. 


being  heated.  Small  objects,  therefore,  such  as 
drills  and  knife-blades,  may  be  heated  on  a  hot 
bar  and  pushed  off  at  the  right  time;  or  small 
drills  may  be  heated  in  the  blue  part  of  the  flame 
of  a  candle,  applied  Just  behind  the  point,  so  that 
the  color  of  the  point  may  be  watched.  Larger 
objects,  such  as  chisels,  cold-chisels,  hatchets,  and 
rock-drills,  may  be  still  more  conveniently  tem- 
pered at  the  edge  by  means  of  the  heat  left  in  the 
rest  of  the  tool  after  the  edge  is  cooled.  The 
making  and  tempering  of  a  cold-chisel  will  afford 
a  good  illustration  of  this  very  useful  method. 

Take  a  bar  of  f'^  octagon  tool  steel.  Cut  off  a 
piece  1'^  long  by  nicking  it  all  round  on  the 
Exercise  35.  Pardee  at  a  red  heat,  cooling  it  quickly 
Making  a  in  Water,  and  then  breaking  it  oif  as 
coid-chisei.  Exercise  26.  Be  careful  not  to  hit 
so  hard  as  to  make  the  piece  fly,  and  not  to  place 
it  in  such  a  position  that,  if  it  does  fly,  it  can  hurt 

anybody.  Working  at  a  red 
heat  and  avoiding  overheat- 
ing, draw  one  end  down  to  a 
bevel  extending  back  about 
2J';  To  do  this,  hold  the 
piece  on  the  anvil,  resting 
obliquely  on  it  at  the  farther 
edge,  as  in  Fig.  5  6,  and  strike 
^iG-  56.  it  with  the  hammer  inclined 

at  a  little  larger  angle.     Both  the  opposite  faces 


HABDENING  AND  TEMPEBING  STEEL. 


101 


will  thus  be  flattened  at  once.  The  angle  of  the 
faces  should  be  about  16°,  which  it  will  be  if 
the  thickness  of  the  steel  is  f^'  and  the  length 
of  the  bevel  2|''.  If  tlie  angle  is  much  larger 
than  this  it  will  not  allow  the  workman  to  have 
a  good  view  of  the  edge  of  the  tool  in  using  it ;  if 
much  smaller,  the  tool  will  be  too  thin  and  will 
spring  too  much.  In  flattening  the  bar  you  will, 
of  course,  spread  it  sideways  also,  as  in  previous 


Fig.  57. 


scarfing  exercises.  Reduce  the  bar  again  nearly  to 
its  former  width  at  the  edge,  by  hammering  on 
the  sides.  Cut  off  the  ragged  edge  at  a  red  heat, 
on  the  hardee,  being  very  careful  not  to  strike  the 
edge  of  the  hardee  with  the  hard  face  of  the  ham- 
mer. It  will  be  safer  to  do  this  with  a  hot-chisel 
and  the  assistance  of  a  helper.  Hold  the  bar  on 
the  anvil  with  the  left  hand,  the  edge  projecting 


102 


FIRST  LESSONS  IN  METAL-WORKING. 


about  over  the  edge  of  the  anvil.  Set  the  hot- 
chisel  over  it,  as  in  Fig.  57,  and  hold  it  w^ith  the 
right  hand  while  the  helper  strikes  it  with  the 
sledofe.  Take  care  that  the  chisel  as  it  cuts 
through  shall  pass  just  clear  of  the  edge  of  the 
anvil,  shearing  the  piece  off  without  injury  to  the 
chisel. 

You  need  not  be  afraid  of  injuring  the  steel  by 
too  much  hammering,  or  by  hammering  after  it 
has  fallen  below  the  red  heat.  Unlike  iron,  it  is 
improved  by  hard  work  on  the  anvil,  having  no 
fibres  which  can  be  separated  by  hammering. 
Finish  the  faces  with  the  flatter,  as  in  Exercise  18. 

You  are  now  ready  for  the  annealing,  harden- 
ing, and  tempering.  Heat  the  whole  chisel  to  a 
cherry-red,  slowly  and  uniformly,  as  explained  in 
Exercises  28-30.  Hold  it  in  the  tongs  by  the 
upper  end  till  it  has  reached  a  black-red  heat,  and 
then  plunge  it  endways,  edge  first,  into  cold 
water,  immersing  it  completely,  and  leaving  it 
there  till  cold.  The  tool  is  now  annealed.  All 
the  inequalities  of  hardness  which  may  have  re- 
sulted from  the  diffei'ent  treatment  that  different 
parts  of  the  tool  have  received  during  the  forging 
are  removed,  and  the  whole  tool  is  soft  enough  to 
be  sharpened  with  a  file. 

To  harden  and  temper  the  edge,  raise  about  2'^ 
at  the  cutting  edge  to  a  red  heat.  Holding  it  in 
the  tongs  with  the  edge  downward,  lower  it  into 


HARDENING  AND  TEMPERING  STEEL.  103 


the  water  to  the  depth  of  about  V\  Then  grad- 
ually raise  it  till  about  half  an  inch  is  immersed, 
and  hold  it  there,  either  still  or  moving  gently  to 
and  fro  sideways,  till  the  edge  is  cold.  The  object 
of  this  movement  upward  is  to  prevent  a  too  ab- 
rupt change  from  the  cold  to  the  warm  part.  If 
the  chisel  is  immersed  to  a  given  depth  and  held 
steadily  there,  the  boundary  between  the  hard  and 
the  soft  part  is  too  distinct,  and  the  chisel  is  al- 
most sure  to  break  at  that  place. 

The  edge  is  now  hard — too  hard  for  use,  and 
is  to  be  tempered.  Rub  one  of  the  surfaces  for 
about  ^'^  back  from  the  edge  with  a  piece  of  sand- 
stone to  brighten  it,  and  then  Avatch  carefully  for 
the  appearance  of  the  proper  color  at  the  edge^  as 
the  heat  comes  along  from  the  other  part  of  the 
chisel.  What  the  proper  color  is,  depends  on  the 
use  to  which  the  tool  is  to  be  put.  We  will 
suppose  this  one  to  be  intended  for  cutting  cast- 
iron,  in  which  case  the  proper  color  is  a  light  pur- 
ple. As  the  colors  move  along  toward  the  edge, 
the  purple  will  be  followed  by  the  dark  blue,  and 
when  the  latter  has  almost  reached  the  edo:e  the 
former  will  have  reached  it,  and  it  is  then  time  to 
plunge  the  whole  chisel  into  water,  and  move  it 
about  till  it  is  cold.  The  experiments  you  have 
already  made  have  taught  you  what  to  do  if  you 
require  a  harder  or  a  softer  temper  than  this. 

The  cutting- angle  of  the  chisel  is  formed  on  the 


104         FIRST  LESSONS  IN  METAL-WORKING. 


grindstone,  and  extends  back  only  about  from 
the  edge.  The  size  of  this  angle,  as  well  as  of 
that  between  the  two  forged  faces,  depends  on  the 
use  to  be  made  of  the  tool.  The  latter  angle  may 
be  12°  to  15°  for  brass  or  copper,  and  16°,  as  in  the 
one  just  made,  for  iron.  The  cutting-angle  should 
be  about  30°  to  35°  for  coj^per,  50°  for  brass,  65° 
for  cast-steel,  and  80°  for  cast-iron. 


HARDENING  AND  TEMPERING  STEEL.  105 


LESSON  XVIIL 

HARDEIS'ING  XNJy  TEMPEEHN^O  ^T^^I.— Continued, 

We  have  next  to  consider — 

3.  The  method  of  cooling.  The  piece  of  steely 
when  heated,  may  be  cooled,  either  for  the  pur- 
pose of  hardening  or  of  tempering  it,  by  plunging 
it  into  any  fluid  which  is  a  good  conductor.  The 
better  the  conductor  is,  the  more  quickly  will  the 
piece  be  cooled,  and  therefore  the  harder  will  it 
be.  Hence,  when  the  highest  degree  of  hardness 
is  required,  mercury  is  sometimes  used.  Water, 
oil,  and  tallo^v,  which  are  inferior  conductors,  give 
successively  lower  degrees  of  hardness.  Water 
is  the  material  most  commonly  used,  and,  for 
pieces  which  require  more  toughness  and  elas- 
ticity, as  springs  and  small  drills,  oil.  In  temper- 
ing also,  as  well  as  in  hardening,  the  fluid  is  varied 
according  to  the  I'esults  sought,  water  and  oil, 
however,  being  generally  used,  and  even  air  when 
the  piece  is  very  small. 

To  illustrate  these  points  we  will  make,  first,  a 
flat  spring,  and  secondly,  a  small  drill. 


106         FIRST  LESSONS  IN  METAL-YiOBKINQ. 


For  the  first,  take  a  piece  of  f round  tool-steel 
about  10''  long.  Heat  3''  of  the  end,  with  proper 
precautions  against  burning,  and  flatten  it  till  it  is 

wide.  Make  it  quite  straight,  and  of  exactly 
Exercise  36.  i^^^^if^^™  width  and  thickucss,  using 
Making  a  a  flatter  if  necessary.  Finish  it  as 
spring.  smooth  and  free  from  scale  as  pos- 

sible, as  scales  will  prevent  it  from  heating  uni- 
formly all  over.  With  a  small  punch  make  two 
holes  in  diameter  in  one  end,  being  careful  not 
to  split  the  piece  in  finishing.  Bend  it  as  in  Fig. 
58,  by  heating  the  end  to  a  dull  red,  laying  it 


over  the  edge  of  the  anvil,  and  hammering  as  in 
Exercise  5.  Be  careful  not  to  make  the  bend  too 
sharp,  but  rather  curved,  or  you  will  weaken  the 
steel  at  that  ])oint.  Bend  the  other  end  in  the 
same  way.  When  the  spring  is  finished,  nick  the 
piece  with  a  file  at  the  base  of  the  spring,  and, 


HARDENING  AND  TEMPERING  81EEL.  107 


holding  it  in  the  vise,  with  the  nick  Just  visible 
above  the  jaws,  break  it  off  by  bending. 

To  anneal  and  harden  the  spring,  provide  a  jar 
of  linseed-oil  four  or  five  inches  deep.  Tie  a  piece 
of  light  wire  8''  or  10'^  long  to  one  end  of  the 
spring  as  a  handle.  Heat  the  spring  to  redness,  in 
melted  lead,  and  let  it  cool  slowly  on  the  ashes 
beside  the  fire.  Heat  it  again  to  redness,  and 
plunge  it  endways  into  the  oil.  If  several  students 
are  working  together,  some  may  try  the  effect  of 
immersing  it  sideways.  You  will  probably  find 
that  in  this  case  the  spring  is  bent  by  the  unequal 
cooling  of  the  opposite  edges,  and  will  thus  learn 
the  advantage  of  immersing  such  pieces  end- 
ways. 

The  spring  being  hardened,  is  now  to  be  tem- 
pered. This  requires  that  it  be  raised  to  the 
temperature  indicated  by  a  deep-blue  color,  or 
about  560°  F.  The  thinness  and  crookedness  of 
the  piece  will  make  it  nearly  impossible  to  do  this 
properly,  either  in  the  fire  or  on  a  red-hot  bar. 
Put  it  into  a  ladel  of  cold  oil,  and  heat  it  gradually 
to  boiling,  with  the  precautions  against  accident 
indicated  on  p.  89.  At  various  stages  in  the 
boiling  the  oil  will  have  different  temperatures, 
which  are  easily  recognized.  When  a  light  white 
smoke  begins  to  come  off,  the  temperature  is  about 
the  same  as  that  indicated  by  a  straw-color,  or 
about  450°  F.    A  copious  dark  smoke  is  equiva- 


108 


FIRST  LESSONS  IN  METAL-WORKING. 


lent  to  a  brown  color,  and  a  still  more  abundant 
black  smoke  to  a  purple.  At  a  little  higher 
temperature  than  this,  the  oil  will  burn  if  ignited, 
but  can  be  put  out  by  blowing  it.  This  tempera- 
ture is  equivalent  to  a  blue  color,  and  will  be 
suitable  for  tempering  the  spring,  if  it  is  made  of 
a  low^-grade  steel.  At  a  still  higher  temperature 
the  oil  swells  up  and  boils  vigorously,  takes  fire 
on  the  surface  and  burns  continuously,  igniting 
again  if  blown  out.  This  temperature  is  suitable 
for  the  spring  if  it  is  made  of  high-grade  steel. 
At  the  proper  temperature,  remove  the  spring 
from  the  oil  by  the  ware  handle,  and  cool  it  in  the 
air,  in  water,  or  in  cold  oil.  The  difference  between 
these  methods  wdll  be  slight  in  such  a  small  piece. 
Set  the  oil  aside  in  the  forge  till  it  cools  off,  after 
which  it  can  be  put  away  for  future  use. 

To  test  the  spring,  hold  it  in  the  vise  by  the 
end,  straighten  it,  and  let  it  go  two  or  three  times. 
It  should  completely  regain  its  figure.  If  it 
breaks,  it  is  too  hard,  and  the  tempering  heat  w^as 
not  high  enough.  If  it  does  not  return,  it  is  too 
soft,  and  the  heat  was  too  great. 

As  a  last  exercise  in  forging  and  tempering 
steel,  make  a  small  drill  such  as  is  shoAvn, 

Exercise  37.  enlarged,  in  Fig.  59.  Take  a  piece  of 
Making  a       stccl  wdrc  y^-g''  thick  and  6''  or  8''  long. 

On  a  small  bench  anvil,  and  using  a 
light  hammer,  draw  it  out,  at  a  dull-red  heat  to 


HAUDENim  AND  TEMPERUSfO  STEEL,  109 


the  form  shown  in  Fig.  59.  The  flame  of  the 
Bunsen  burner  may  be  used 
for  this,  or  the  forge-fire,  if 
very  great  care  is  taken.  First 
draw  out  the  narrow  part,  or 
shank  of  the  drill,  turning  it 
constantly  to  preserve  its 
roundness  and  keeping  it  quite 
straight.  Next  flatten  and 
widen  the  end.  Finish  it 
smooth,  cut  it  off,  and  anneal 
it  at  a  black-red  heat.  Finish 
the  flat  faces  on  the  grind- 
stone, and  then  form  the  two 
bevelled  surfaces,  by  holding 
it  on  the  grindstone  or  the 
emery-wheel  as  in  Fig.  60, 
cutting  it  back  to  the  dotted 
line,  and  then  turning  it  over 
and  cutting  to  the  other  dotted 
line.  Observe  that  the  faces 
that  you  are  now  forming  are 
to  be,  as  shown  at  b  and 
not  perpendicular  to  the  flat 
faces,  but  inclined  to  them 
The  inclination,  which  constitutes  the  cutting- 
angle  of  the  tool,  depends,  as  in  all  other  cutting 
tools,  on  the  hardness  of  the  material  on  which  it 
is  to  work.    If,  as  you  hold  the  drill  between  the 


110 


FIRST  LESSONS  IN  METAL- WORKING. 


tliumb  and  finger  in  grinding  it,  you  turn  tlie 
thumb  a  very  little  over  toward  the  right,  you 
will  make  a  drill  suitable  for  one  kind  of  work, 
and  if  you  turn  it  a  little  farther,  one  suitable  for 
softer  material.  Your  drill,  when  finished,  will 
have,  as  you  see  on  examining  the  figure  or  the 
drill  itself,  not  a  point,  but  a  short  blunt  edge, 
running  obliquely  across  the  end,  as  shown  in  the 
end  elevation  O. 


Fig.  60. 


The  drill  is  now  to  be  hardened  and  tempered. 
To  harden  it,  hold  the  point  in  the  flame,  watch 
it  till  it  reaches  a  cherry-red,  and  then  plunge  it 
into  water.  The  butt  of  the  drill  wnll  thus  be 
left  soft.  Brighten  the  point,  and  hold  it  again 
in  the  flame,  the  point  being  this  time  just  out- 
side, so  that  the  color  can  be  seen.  The  color, 
which,  in  the  case  of  such  a  small  piece  as  this, 
will  appear  very  soon,  should  be  brownish  yellow 
if  the  drill  is  intended  for  iron,  and  purple  if  it  is 
for  wood.  The  moment  the  color  appears,  plunge 
the  drill  quickly,  point  downwards,  into  cold  oil. 


HARDENING  AND  TEMPERING  STEEL,  111 


The  final  finishing  on  the  grindstone  is  done  after 
the  tempering. 

A  still  smaller  drill  may  be  hardened  by  heat- 
ing the  point  in  a  candle-flame,  and  cooling  it  in 
the  tallow  of  the  candle.  It  is  then  tempered,  by 
covering  the  point  lightly  with  tallow,  holding 
the  stem  Just  behind  the  point  in  the  flame  till  it 
begins  to  give  off  a  white  smoke,  and  then  cooling 
it  either  in  the  tallow  or  in  the  air. 

The  exercises  in  hardening  and  tempering  that 
you  have  now  gone  through  will  give  you  a  sufii- 
cient  comprehension  of  the  general  principles  of 
the  process.  A  great  variety  of  modifications  of 
the  methods  will  be  needed  for  works  of  different 
sizes  and  shapes,  and  intended  for  different  uses ; 
but  these  will  be  easily  understood  when  the 
necessity  for  them  arises. 

It  might  be  supposed  that,  as  cast-iron  differs 
from  steel  in  the  same  way  that  steel  differs  from 
wrought-iron,  namely,  in  having  more  carbon  in 
its  composition,  it  might  be  hardened  and  soft- 
ened in  the  same  way.  This  is  to  a  certain  extent 
true.  Cast-iron  can  be  hardened  by  rapid  cooling ; 
but  it  requires  a  much  higher  temperature  for  the 
purpose  than  steel  does.  It  must  be  cooled,  not 
merely  from  a  red  heat,  but  from  the  melting  heat. 
If  cast-iron,  when  melted  is  poured  into  moulds 
of  damp  sand  or  of  metal,  it  becomes  very  hard 
on  the  surface.     Such  metal  is  called  chilled 


112 


FIRST  LESSONS  IN  METAL- WORKING, 


iron,"  and  is  sometimes  used  when  great  hardness 
is  required  at  moderate  expense,  and  without  re- 
gard to  toughness,  as  in  ploughshares,  ore-stamps, 
rollers  for  pressing  or  crushing,  and  sometimes  in 
tools  for  turning  iron  and  steel.  Such  metal, 
however,  is  brittle  and  cannot  be  tempered,  and  is 
not  a  fit  substitute  for  steel  in  most  of  the  uses  to 
which  the  latter  is  put. 

Even  when  cast-iron  is  not  intentionally  chilled, 
it  is  unavoidably  hardened  on  the  surface  by  the 
chilling  action  of  the  mould,  and  this  is  one  of 
the  reasons  why  the  hard  ^^skin"  is  commonly  re- 
moved with  the  chisel  or  planing-machine  before 
applying  the  file. 

As  cast-iron  can  be  hardened  by  chilling,  so 
wrought-iron  can  be  hardened  on  the  surface  by 
baking  it,  at  a  red  heat,  while  surrounded  with 
powdered  carbon.  The  resemblance  between  this 
process  and  that  of  steel-making  by  cementation 
is  seen  at  a  glance.  Indeed,  it  is  an  imperfect 
conversion  of  the  iron  into  steel  on  the  surface. 
It  is  called  "  case-hardening,"  and  is  used  for  such 
objects  as  the  wearing  parts  of  gun-locks,  the  ends 
of  axles,  and  other  objects  exposed  to  great  wear 
by  rubbing. 

Finally,  as  wrought-iron  can  be  hardened,  so, 
by  an  almost  exactly  opposite  process,  cast-ii'on 
can  be  softened.  As  wrought-iron  is  hardened 
by  absorbing  carbon,  so  cast-iron  is  softened  by 


HARDENING  AND  TEMPERING  STEEL.  113 


being  made  to  give  up  carbon.  For  this  purpose 
it  is  packed  in  a  substance  containing  oxygen, 
such  as  lime  (calcium  oxide)  or  the  scales  from 
the  blacksmith's  forge  (iron  oxide),  and  baked  at 
a  red  heat.  A  part  of  the  carbon  combines  with 
the  oxygen,  and  escapes  as  carbonic  oxide,  leaving 
an  iron  with  a  lower  percentage  of  carbon,  and 
therefore  resembling  wrought-iron  or  mild  steel. 
Such  iron  is  called  "  malleable"  iron,  and  is  much 
used  for  small  articles  which  require  more  tough- 
ness than  cast-iron  possesses,  but  which  are  to  be 
made  in  large  numbers,  and  w4th  a  cheapness  ap- 
proaching that  of  cast-iron.  Hinges,  gate-fixtures, 
parts  of  harness,  and  a  great  number  of  small 
household  articles  are  made  in  this  way. 

It  must  be  understood,  however,  that  not  every 
kind  of  pig-iron  can  be  used  for  the  several  kinds 
of  iron  that  have  been  described,  but  that  one  pig 
or  another,  or  a  mixture  of  several,  must  be  used, 
according  as  high  or  low  steel,  foundry  iron, 
chilled  iron,  good  forge  iron  or  malleable  iron  is 
required;  and  great  skill  and  experience  are 
necessary  to  enable  the  iron-manufacturer  to  make 
the  proper  selection  in  each  case. 


114 


FinSl  LESSONS  IN  METAL-  WORKING. 


LESSON  XIX. 
CHippiisra. 

Objects  made  of  iron,  steel,  or  brass  by  casting 
are  frequently  too  rough  to  be  used  in  the  foim 
in  which  they  come  from  the  mould,  and  have  to 
be  finished  up  by  filing,  grinding,  scraping,  and 
polishing.  Sometimes,  also,  it  is  necessary  to  take 
off  more  metal  than  can  be  conveniently  removed 
by  the  file.  On  large  and  flat  surfaces  this  may 
be  accomplished  by  means  of  a  planing-machine ; 
but  on  surfaces  that  are  small,  or  of  such  a  shape 
that  the  planer  cannot  reach  them,  the  part  to  be 
removed  is  taken  oft*  by  "chipping"  with  a  cold- 
chisel,  that  is,  a  chisel  which  can  be  used  without 
first  softening  by  heat  the  substance  which  is  to 
be  cut. 

Two  kinds  of  chisel,  shown  in  Fig.  61,  are  used. 
The  first,  called  a  "  cape"  or  cross-cut"  chisel,  is 
made  thin  at  but  is  widened,  as  shown  at 
to  give  it  the  needed  sti'ength.  It  is  used  in  cut- 
ting grooves.  Being  thinned  at  a  little  distance 
back  from  its  edge,  it  can  be  driven  along  the 


CRIPPING. 


115 


groove  without  catching  at  the  sides,  while  the  ex- 
tra width  at  a  prevents  its  spiinging  "  under  the 
blow.  The  other,  is  the  "  finishing  "  or  plan- 
ing "  chisel,  and  is  used  for  cutting  broader  plane 
surfaces.    It  is  sometimes  ground  with  a  slightly 


T 


 L 


curved  edge,  in  which  case  a  very  thin  cut  can  be 
made  at  the  middle  while  the  corners  are  not 
cutting  at  all.  Its  action  in  this  case  is  much  like 
that  of  the  jack-plane,  and  leaves  a  series  of  shal- 
low valleys  on  the  surface  that  is  finished  with  it. 


116 


FIRST  LESSONS  IN  METAL-  WORKING. 


The  chisel  is  tempered,  as  in  Lesson  XVI,  to  a 
color  which  may  range  from  yellow  to  purple,  ac- 
cording to  the  work  it  is  to  do.  It  will  splinter 
if  it  is  too  hard,  and  will  turn  up  or  become 
rounded  on  the  edge  if  too  soft,  and  must  then  be 
re-tempered.  In  any  case,  its  edge  must  be  kept 
sharp  by  frequent  use  of  the  grindstone.  The 
angle  also  depends  on  the  kind  of  work,  as  has 
been  explained  in  Lesson  XVII. 

As  an  exercise  in  the  use  of  the  chipping-chisel, 
M^e  will  remove  from  the  surface  of  a  cast-iron 
block  3^^  square.  We  will  first  cut  three  grooves 
Exercise  38.  i  ' ^^ide  to  the  required  depth,  leaving 
Chipping  four  surfaccs  y^-g^'  wide  to  be  after- 
cast-iron,  wards  cut  down  Avith  the  finishing- 
chisel.  It  will  be  found  that  the  work  can  be 
done  more  easily  in  this  way  than  by  cutting  the 
whole  surface  at  once  with  the  finishing-chisel. 
Lay  out  the  face  of  the  block  for  this  work  by 
first  rubbing  it  all  over  with  chalk,  and  then 
drawing  the  necessary  lines  with  a  sharp-pointed 
steel  ^^scriber"  or  marking-tool.  Mark  also,  on 
the  edge,  a  line  showing  the  depth  to  which  the 
work  is  to  be  cut.  Put  the  block  in  one  of  the 
heaviest  vises  on  your  bench.  If  there  is  a  ^'  leg- 
vise,"  Fig.  62,  use  this,  as  being  firmer  than  any 
other.  Place  the  block  in  the  vise,  with  the  lines 
indicating  the  grooves  perpendicular  to  the  jaws, 
and  with  the  U23per  surface  of  the  block  only  just 


cHippim. 


117 


above  the  edge  of  the  jaws,  and  fasten  it  very 
firmly.  Make  sure  that  the  head  of  the  chisel 
and  the  face  of  the  hammer  are  quite  free  from 
any  trace  of  grease,  by  rubbing  them  on  the  dusty 


Fig.  62. 

floor.  You  will  tlius  lessen  the  chance  of  the 
hammer's  glancing  off  and  striking  your  hand. 

In  vise-work  hold  the  hammer  less  tightly  than 
in  forge-work.  Let  it  turn  somewhat  loosely  be- 
tween the  forefinger  and  the  thumb. 

To  begin  the  chipping,  set  the  edge  of  the 


118 


FIBST  LESSON'S  IN  METAL- WOBKING. 


chisel  at  one  end  of  the  line  drawn  on  the  face, 
and,  holding  it  horizontally,  strike  it  a  vigorous 
blow,  cutting  off  a  triangular  chip,  and  making  a 
chamfer  or  bevel,  as  shown  by  the  dotted  line  in 
Fig.  63.  Extend  this  along  the  whole  length  of 
the  end  of  the  block,  thus  marking  conspicuously 
the  depth  to  w^hich  the  metal  is  to  be  removed. 
Turn  the  piece  in  the  vise,  and  cut  a  similar  cham- 
fer round  each  of  the  other  pieces  in  succession. 


Fig.  63. 

Now,  using  the  cape-chisel,  set  it  on  the  bev- 
elled surface,  at  the  end  of  one  of  the  proposed 
grooves,  and  with  the  edge  about  below  the 
upper  surface,  as  in  Fig.  64.  Incline  the  handle 
upwards,  so  that  the  lower  cutting-face  shall  make 
a  very  small  angle,  abdy  with  the  intended  direc- 
tion of  the  cut,  ahc.  Hold  the  chisel  firmly,  near 
the  upper  end,  and  keep  your  eye  on  the  cutting- 
edge,  not  on  the  handle.  Using  a  hammer  of 
about  If  to  2 J  lbs.  weight,  with  a  handle  13''  to 
14^'  long,  which  you  hold  near  the  end,  strike 
the  chisel  with  a  vigorous  swing  of  the  hammer 
from  the  elbow.    Be  careful  to  strike  exactly  in 


CHIPPING. 


119 


tLe  direction  of  tlie  length  of  the  cliisel,  so  that 
it  shall  not  receive  any  twist  from  the  blow,  but 
move  directly  forward.  It  will  cut  off  and  curl 
up  a  stout  chip,  exactly  as  the  iron  of  the  jack- 
plane  does,  and  being  continually  driven  forward, 
will  work  a  shallow  groove  across  the  block.  It 
is  important  that  you  should  hold  the  chisel  at 
the  proper  inclination.    If  the  handle  is  held  too 


Fig.  64.  \ 

low,  as  in  Fig.  65,  the  edge  w^ill  be  inclined  up- 
ward at  and  the  tool  will  run  up  and  leave  the 
cut.  If  it  is  held  too  high,  as  in  Fig.  66,  the 
point  will  be  driven  too  far  into  the  metal,  and 
the  cut  will  become  so  deep  that  the  chip  will 
not  curl  up  and  break  off,  but  the  tool  will  be 
brought  to  a  standstill. 

After  the  cut  is  started,  you  yviWfeel  the  proper 


120         FIE8T  LESSON'S  IN  METAL-WORKING. 

position  of  tlie  chisel,  by  rocking  it  uj)  and  down 
slightly,  as  you  would  rock  a  wood-chisel  on  the 
oil  -  stone,  to  ascertain  when  the  bevel  -  surface 
touches  the  stone  properly. 


Fig.  66. 


It  is  important,  also,  to  strike  powerful  blows 
with  a  free  swing  of  the  hammer  from  the  elbow. 
Light  blows  often  repeated  will  not  serve  the 
same  purpose :  they  w^ill  not  cut  and  shatter  the 


CHIPPING. 


121 


metal.  You  may  stiike  light  blows  at  first,  to 
get  your  aim  sure  and  your  hand  steady,  but  they 
will  not  have  much  effect  on  the  metal.  Even  at 
the  risk  of  striking  your  left  hand  occasionally, 
you  must  hit  hard. 

In  cutting  the  grooves,  stop  at  about  ^  from 
the  end,  and  cut  the  opposite  way,  to  avoid  splin- 
tering the  metal. 

In  cutting  wrought-iron,  steel,  or  brass,  wet  the 
edge  of  the  chisel  occasionally,  by  pressing  it  on 
a  bit  of  wet  rag  or  cotton-waste  kept  for  the  pur- 
pose. 

A  second  and  a  third  cut  being  made  in  the 
same  way  as  the  first,  you  will  cut  one  of  the 
grooves,  and  afterwards  all  the  others,  down  to 
the  required  depth.  Be  careful  not  to  go  below 
this  depth  at  any  jjoint ;  to  fall  short  of  it  will 
do  less  harm. 

Having  cut  all  the  grooves  with  the  cape- 
chisel,  cut  down  the  bands  between  them  with 
the  planing-chisel.  If  you  have  cut  the  grooves 
to  just  the  right  depth,  they  will  afford  such  per- 
fect guidance  to  your  chisel  that  you  will  cut  the 
rest  of  the  surface  with  comparative  ease. 

If  the  work  has  been  well  done,  the  surface 
will  be  imiformly  marked  all  over  with  parallel 
shallow  notches,  about  equidistant  and  of  equal 
depth,  indicating  the  successive  forward  steps  of 
the  chisel.    In   perfect  work,  indeed,  no  such 


122 


FIRST  LESSOJSrS  IN  METAL-WORKING. 


notches  would  be  seen,  because  each  forward 
movement  would  be  in  the  continuation  of  the 
preceding  cut.  In  practice  such  a  result  is  not 
to  be  expected ;  but  you  should  aim  to  come  as 
near  it  as  possible. 

The  chipping  of  brass  is  similar  to  that  of  cast- 
iron.  The  tool,  however,  may  be  thinner,  and 
have  a  smaller  angle,  as  already  explained.  It 
may  also  be  wider  (say  1^'),  as  the  same  blow  that 
will  drive  a  narrow  chisel  through  cast-iron  w411 
drive  a  wider  one  in  brass.  For  an  exercise  in 
brass-chipping,  take  the  block  prepared  as  a  foun- 
dry exercise,  page  64,  Fig.  50,  and  chip  it  to  the 
form  of  a  hexagonal  prism. 

First,  whitening  the  ends,  lay  out  the  bases  of 
the  prism.    Find  the  centre  of  each  end  by  draw^- 

z  rn      ing  diagonals,  and  mark  it 

lightly  with  a  centre  punch. 
^      With  a  compass,  draw  round 
this    the   inscribed  circle. 
^      From     Fig.  67,  draw  a  line 
n      on  the  rectangular  face  of 
Fig.  67.  the  prism,  parallel  to  the 

edge,  thus  finding  the  corresponding  point  on  the 
other  base,  and  draw  the  inscribed  circle.  Start- 
ing from  lay  otf  chords  equal  to  the  radius,  find- 
ing thus  the  points  J,  ejf.  Draw  the  hexagon 
on  each  end  of  the  piece.  Connect  the  vertices 
aa  and  dd  of  the  two  hexagons,  by  lines  drawn 


CHippim. 


123 


on  tlie  faces  of  the  block.  Pi'olong  ah^  dc^  af^  de^  as 
in  tlie  fi^-ure.    Connect  the  points  qq, 

,  .  Exercise  39. 

i%  of  tlie  two  bases  by  lines  on  laying  out  a 
the  faces  of  the  block.  If  now  you  cut  hexagonal 
off  first  the  four  pieces  which  have  the  p^^^"^" 
bases  amg^  lind^  doi,,  and  alh^  you  will  make  a  hex- 
agonal prism,  whose  bases,  however,  are  not  regu- 
lar. On  the  faces  of  this  prism  draw  hb^  cCy  ee^  and 
ff\  and  cut  away  the  parts  whose  bases  are  hgJic 
and  hfei^  and  the  prism  will  be  complete. 

To  cut  off  all  these  parts,  first  hold  the  block 
endways  in  the  vise,  its  edges  perpendicular  to  the 
Jaws  and  the  line  parallel  to  them.  Beginning 
near  on^  cut  off  a  piece  along  the  whole  edge  mm, 
Just  as  in  the  last  exercise.  As  the  chisel  ap- 
proaches the  end  of  the  cut,  turn  the  piece  round 
and  cut  in  the  opposite  direction,  so  as  not  to 
splinter  the  base.  Repeat  this  till  you  have  cut 
down  to  ag^  being  careful  not  to  go  beyond.  The 
first  cuts,  being  narrow,  may  be  deeper  than  the 
succeeding  ones.  Repeat  this  operation  at  the 
other  three  corners.  Then,  having  drawn  the 
new  lines  bh^  cc^  ^^^ff^  off  the  remaining  por- 
tions in  the  same  way.  If  you  have  not  cut  quite 
down  to  the  required  surfaces  at  first.  Exercise  40. 
you  may  use  a  thinner  and  sharper  Chipping 
chisel  and  a  lighter  hammer  for  the 
finish,  making  constant  use  of  a  straight-edge  and 
a  "template''  or  plate  of  brass,  Fig.  68,  whose 


124 


FIRST  LESSONS  IN  METAL-  WORKING. 


angle  is  120°,  to  make  sui'e  that  you  are  not  cut- 
ting anywhere  too  deep.  Having  made  one  face 
as  straight  and  smooth  as  possible,  and  free  from 
winding  (AVood-working,  page  54),  apply  the  tem- 
plate repeatedly  to  this  while  working  the  next 
face,  so  as  to  give  the  next  the  proper  inclina- 
tion to  this.  When  the  tw^o  faces  adjacent  to  the 
first  are  finished,  give  the  next  two  the  proper 
inclination  to  these.  If  this  has  been  correctly 
done  it  will  be  easy  to  give  the  last  face  the 
proper  inclination  to  the  two  preceding  ones.  In 


Fig.  68. 


applying  the  template,  it  is  of  the  utmost  impor- 
tance that  both  arms  of  it  should  be  exactly  per- 
pendicular to  the  edge  of  the  prism  which  lies  be- 
tween them  ;  otherwise  you  w'ill  make  the  angle 
of  the  prism  too  obtuse.  Very  close  attention  to 
this  is  absolutely  necessary,  as  is  also  perfect  cor- 
rectness in  the  angle  of  the  template  itself.  Of 
course,  if  the  two  bases  have  been  drawn  exactly 
correct  and  with  their  corresponding  sides  parallel, 
you  have  only  to  cut  down  to  these  lines  and  then 
work  with  the  straight-edge  alone,  the  template 


CHIPPING, 


125 


being  unnecessary ;  but  your  work  will  hardly  be 
exact  enough  for  this. 

The  faces  of  the  prism  being  finished,  the  bases 
are  to  be  cut  off  in  the  same  way,  perpendicular 
to  the  faces,  and  ^^-^'^  apart,  the  work  being  tested 
as  it  proceeds  with  straight-edge  and  square.  The 
result  should  be  a  true  hexagonal  prism  2^^-''  high, 
its  opposite  faces  being  equal  and  parallel  rectan- 
gles, its  edges  straight,  and  its  angles  all  equal  to 
that  of  the  template.  There  should  be  no  marks 
extending  conspicuously  below  the  general  sur- 
face so  that  they  cannot  be  easily  removed  by  the 
file,  as  in  a  later  lesson. 


126 


FIRST  LESSONS  IN  METAL-  WORKING. 


LESSON  XX.  • 

DEILLma  AT^D  SAWING. 

In  the  chipping  exercises  just  finished,  no  large 
amount  of  metal  had  to  be  removed,  though  the 
quantity  to  be  cut  away  was  larger  than  it  would 


klr- 

 8-cmr  A 

) 

t 

B 

Fig.  69. 

be  proper  to  attack  with  the  file.  In  some  cases 
a  larger  piece  has  to  be  removed,  as  when  a  cor- 
ner is  to  be  cut  out  of  a  block  of  metal  or  a 
slot  to  be  made  in  one,  as  B.  In  such  a  case  the 
piece  is  cut  out  with  a  ^^lack-saw,"  Fig.  70.  The 
teeth  of  this  saw  have  their  front  edges  perpendi- 
cular to  the  edge  of  the  saw,  and  their  back  edges 
inclined  to  it,  as  in  the  rip-saw  (Wood- working,  p. 


DRILLim  AND  SAWING, 


127 


83).  Tliey  therefore  cut  under  the  metal,  some- 
what as  a  chippiiig-chisel  does,  removing  the  metal 
in  small  chips,  like  the  saw  dust  from  a  wood-saw. 
Its  teeth  have  no  "  set,"  as  those  of  wood-saws 
generally  have,  but  are  sometimes  made  a  little 
thicker  than  the  back  of  the  blade,  by  setting  the 
saw  up  on  its  back  edge  on  a  block  of  hard  wood 
before  sharpening  it,  and  hammering  the  points 


Fig.  70. 


of  the  teeth  lightly.  This  not  only  spreads  them 
out  sideways  and  gives  the  tool  the  extra  thick- 
ness on  the  edge  which  makes  it  run  freely,  but 
at  the  same  time  brings  the  points  of  the  teeth 
into  a  straight  line.  This  is  very  essential  to  the 
proper  working  of  a  saw,  whether  in  wood  or  in 
metal.  If  any  of  the  teeth  stand  up  above  the 
rest,  they  catch  in  the  work  and  make  the  saw 
Jump  and  chatter."  Sometimes  this  thickening 
of  the  edge  of  the  teeth  is  omitted,  the  burr"  or 
roughness  left  by  the  file  being  sufficient  to  give 
the  needed  set." 

The  cutting  of  the  slot         Fig.  69,    Exercise  41. 

in  a  plate  of  V'  brass  will  be  a  good  i>riiiing. 
exercise  in  the  use  of  the  saw  and  of  the  "ratchet- 


128         FIRST  LESSONS  IN  METAL- WORKING. 


drill.'^    The  slot  is  commenced  by  boring  two  holes 

for  its  ends  with  the 
hand-drilling  machine, 
Fig.  71,  or  the  ratchet- 
drill,  Fig.  72.  Mark 
the  exact  positions  of 
the  centres  of  the  holes 
with  a  centre-pulich. 
Provide  a  drill  1  cm. 
wide,  such  as  you  made 
in  Exercise  37.  If  you 
have  not  one  of  exactly 
the  rio;ht  width,  alter  a 
wider  one,  l)y  reducing 
it  on  the  grindstone, 
being  careful  to  reduce 
both  sides  equally. 

The   ratchet-drill  is 
made  in  various  forms, 
Fig.  71.  bnt  the  essential  pi'in- 

ciple  of  all  is  the  same.  The  work  to  be 
drilled  rests,  at  on  blocks  supported  on  the 
frame-work  B,  which  may  be  screwed  to  the 
bench.  A  screw  (7,  which  must  be  turned  by 
hand  as  the  boring  progresses,  or  else  a  lever 
worked  by  the  hand  of  an  assistant,  presses  the 
drill  IJ  down.  A  lever  or  handle  provided 
with  a  spring  pawl "  concealed  in  the  box 
turns  on  the  axis  or  shaft  of  the  drill.    The  pawl 


DRILLING  AND  SAWING. 


129 


slips  by  the  teetli  of  a  toothed  wheel  which  is  at- 
tached to  the  axis,  when  the  handle  is  turned  in 
one  direction,  but  catches  the  teeth  and  turns  the 
drill  when  moved  in  the  opposite  direction.  The 
hand-drilling  machine,  Fig.  71,  is  used  for  the 
same  purpose,  and  is  even  more  convenient. 


Fig.  72. 


Setting  the  plate  on  the  bottom  of  the  frame- 
work of  the  drill,  and  supporting  it  on  blocks,  if 
necessary,  to  raise  it  to  the  proper  height,  turn  the 
screw  at  the  top  till  you  bring  the  point  of  the 


130 


FIRST  LESSONS  IN  METAL-  WORKING. 


drill  down  into  the  holemade  by  the  centre-punch. 
Fasten  the  work  so  that  it  cannot  turn.  Turn  the 
drill  by  means  of  the  handle,  and  keep  moving  it 
down  at  the  same  time  by  means  of  the  "  feed 
screw.  Lubricate  the  point  w^ith  oil  or  with  soap 
and  water  in  cutting  brass,  w^rought-iron,  or  steel ; 
for  cast-iron  this  is  not  necessary.  Do  not  feed  " 
or  force  the  drill  forward  too  fast,  or  you  will 
break  it,  or  spoil  its  temper.  Let  the  drill,  when 
it  comes  through,  come  out  into  a  hole  in  the  sup- 
port, or  else  have  a  block  of  wood  immediately 
under  the  work. 

The  two  holes  being  bored,  draw  two  parallel 
lines  tangent  to  them  w^ith  the  scriber,  thus  mark- 
Exercise  42.  ^^^^  ^^^^  ^^^^  shape  of  the  piece  to 
Cutting  a  be  rcuiovcd.  Holding  the  piece  in  the 
vise,  and  using  a  square  file,  cut  one  of 
the  holes  to  the  shape  shown  in  Fig.  73,  forming 

thus  flat  sides  against  which 
the  sides  of  the  saw  can  rest. 
Loosening  the  screw  at  the 
end  of  the  saw-frame,  un- 
hook the  saw,  put  the  blade 
through  the  hole,  hook  it  and 
'^*^*  tighten  it  again,  and  cut  down 

to  the  other  hole.    Use  oil  to  make  the  saw  work 
freely,  except  in  cast-iron.    Do  not  press  too  hard, 
and  be  careful  not  to  run  outside  of  the  line. 
The  first  cut  being  made,  carry  the  saw  back 


DRILLING  AND  SAWING. 


131 


to  tlie  first  hole,  and  cut  the  second  line  in  the  same 
way.  The  piece  between  the  lines  being  removed, 
the  rouo-hly  framed  slot  can  be  finished  with  the 
file  as  in  the  next  lesson. 

Such  a  piece  is  sometimes  removed  by  boring 
a  series  of  holes  close  together  along  the  whole 
length  of  the  slot,  and  then  cutting  away  the  metal 
between  them  with  a  round  file. 


132 


FIMST  LESSONS  IJST  METAL- WORKING. 


LESSON  XXL 

FILIlsrG. 

After  chipping  and  sawing,  the  work  is  ready 
to  be  smoothed  w^ith  the  file. 

The  file  is  a  series  of  small  chisels,  finer  or 
coarser  according  to  the  work  required  of  them. 
These  minute  chisels  are  made  by  cutting  numer- 
ous fine  grooves  very  close  together  in  a  bar  of 
steel  shaped  as  in  Fig.  74.  If  only  one  such  set 
of  gi'ooves  is  cut,  the  file  is  called  a  single-cut " 
file  or  float,"  and  appears  as  shown  in  the  upper 
part  of  Fig.  74,  a.  The  appearance  of  the  teeth 
is  shown,  magnified,  at  d.  The  w^hole  face  of  the 
file  is  thus  a  series  of  chisels,  each  having  a  breadth 
equal  to  the  length  of  one  of  the  lines  in  a,  inclined 
to  the  axis  of  the  file  at  an  angle  of  35°  to  55°, 
and  having  their  sharp  edges  turned  towards  the 
point  of  the  file.  Files  of  this  sort  are  only  used 
for  soft  materials,  such  as  wood,  horn,  and  lead. 
When  very  coarse,  as  in  the  case  of  the  files  used 
for  lead,  the  cuts  are  almost  pei'pendicular  to  the 
len2:th  of  the  file.  The  files  used  for  such  work 
as  you  will  undertake,  or  for  metal- work  in  gen- 


FILING, 


133 


eral,  have  two  such  sets  of  grooves,  and  are  called 
double-cut."    The  first  cuts  are  made  as  already- 
described,  and  the  second,  which  are  not  quite  so 
deep,  cross  these,  as  sliow^n  in  the  lower  part  of 


Fig.  74. 


the  figure,  being  inclined  to  the  axis  in  a  direction 
opposite  to  the  first,  at  an  angle  of  from  75°  to  85°. 
The  wide  chisels  of  the  first  cut  are  thus  divided 
into  a  large  number  of  small-pointed  teeth.  The 
teeth  of  any  one  row  being  pushed  across  the 


134 


FIRST  LESSONS  IN  METAL-  WORKING. 


work  would  make  a  series  of  fine  grooves  ;  but  the 
teeth  of  the  next  rows  following  these,  cut  down 
the  ridges  between  these  grooves,  and  so  gradually 
2:)lane  the  work  down. 

Double-cut  files  have  various  names  to  distin- 
guish the  degrees  of  fineness  or  the  closeness  of 
the  grooves.  These  names  differ  somewhat  in 
the  different  regions  in  which  files  are  made,  the 
Lancashire  names  and  the  Sheffield  names,  for 
instance,  being  not  exactly  the  same.  Without 
learning  both  series  of  names  it  will  be  sufficient 
to  remember  that,  in  both  sets,  the  coarsest  files 
are  called  rough,"  and  the  very  fine  ones 
^^smooth."  Intermediate  ones,  following  the  rough, 
are  "bastard"  and  "second-cut,"  and  a  still  finer 
kind  than  the  smooth  are  called  "  dead-smooth"  or 
"  superfine." 

It  may  be  remembered  also  that  the  "rough" 
Lancashire  files  have  from  21  to  56  cuts  to  the 
inch,  the  "smooth"  from  56  to  112,  and  the  "su- 
perfine" as  many  as  300  in  the  case  of  the  small- 
est files. 

The  grooves  are  cut  with  a  chisel  while  the  file 
is  soft,  and  it  is  then  hardened  and  tempered  ac- 
cording to  the  kind  of  work  it  is  to  do,  and  the 
"  tang"  or  pointed  end  is  softened  to  prevent  its 
breaking. 

The  description  of  the  mode  of  cutting  the 

*  Holzapfel:  Turning  and  Mechanical  Manipulation. 


FILING, 


135 


teeth  of  a  double-cut  file,  or  an  inspection  of  the 
teeth  with  a  magnifying-glass,  will  convince  you 
that  files  are  delicate  tools,  and  that  they  can  be 
easily  injured  by  improper  treatment.  A  few 
precautions  may  be  given  here  to  enable  you  to 
avoid  the  commonest  errors,  and  others  will 
come  to  your  notice  afterwards,  as  your  work  pro- 
gresses. 

1.  A  new  file  must  not  be  used  on  wrought-iron 
or  steel.  These  can  be  cut  with  a  file  that  is 
partly  worn,  but  cast-iron  and  brass  require  new 
and  sharp  files. 

2.  No  file,  unless  it  be  one  that  is  almost  worn 
out,  should  be  used  on  chilled  castings.  The  sur- 
face of  a  casting  should  be  carefully  tried  with  an 
old  file,  and  if  it  is  found  to  be  very  hard,  the 
skin  must  be  removed  on  the  grindstone. 

3.  No  file  should  be  used  on  castings,  whether 
hard  or  soft,  in  the  state  in  which  they  come  from 
the  foundry.  The  surface  is  covered  with  sand, 
which  will  spoil  any  file.  This  is  sometimes  re- 
moved by  "  pickling"  in  dilute  sulphuric  acid, 
which  eats  away  a  portion  of  the  iron  and  loosens 
the  sand  so  that  it  can  be  washed  off.  When  the 
figure  of  the  casting  is  such  that  the  surface  can- 
not be  reached  by  the  grindstone,  this  is  the  only 
effectual  method,  except  chipping,  of  preparing 
the  work  for  the  file. 

4.  The  file  should  always  be  relieved  from  pres- 


136 


FIE8T  LESSONS  IN  METAL-WOBKING. 


sure  while  it  is  being  drawn  back,  as  heavy  pres- 
sure on  the  backs  of  the  teeth  breaks  them  off. 
It  is  not  necessary,  however,  to  lift  the  file  from 
the  work,  but  only  to  lessen  the  pressure. 

5.  The  teeth  of  the  file  should  be  kept  clean. 
They  are  apt  to  become  "  clogged,  or  "  pinned  "  by 


A 


Fig.  75. 

the  dust  cut  off,  which  must  then  be  removed. 
This  can  be  done  in  several  ways.  The  "pins" 
may  be  pushed  out  with  a  pointed  steel  wire.  Fig. 
7 5,  A.  They  may  be  brushed  out  with  a  wire  file- 
brush,  B,  of  fine  brass  or  steel  wire,  bound  into  a 
bundle  with  the  ends  projecting;  or  they  may  be 
raked  out  with  the  scraper,  c,  made  of  a  piece  of 
sheet-brass  hammered  to  an  edge  and  bent  at  right 


FILING, 


137 


antrles,  into  whicli  the  teetli  of  tlie  file  will  cut 
when  it  is  drawn  over  them,  allowing  the  inter- 
mediate points  to  penetrate  into  the  grooves  and 
clear  them. 

The  file  should  be  fitted  with  a  handle  of  soft 
wood.  To  put  the  handle  on,  hold  the  file  in  the 
vise,  protecting  it  from  the 
steel  Jaws  by  false  Jaws 
of  lead,  A,  Fig.  76,  and 
leaving  the  tang  project- 
ing forward.  Then,  tak- 
ing the  handle  in  the  hand,  push  the  tang  into  it, 
turning  the  handle  at  the  same  time,  to  let  the 
tang  bore  its  way.  Take  the  handle  off  and 
knock  out  the  shavings,  and  repeat  the  operation 
till  the  tang  has  entered  about  three  quarters  of 
its  length,  or  a  little  more,  leaving  the  rest  for 
future  use  as  the  handle  wears  loose.  The  handle 
is  sometimes  fitted  by  heating  the  tang  to  redness 
and  pushing  it  in,  letting  it  burn  its  way.  This 
method  is  objectionable,  however ;  first,  because 
of  the  risk  of  overheating  the  file,  and  secondly, 
because  the  charred  wood  wears  away  soon^  and 
lets  the  handle  come  loose. 

Besides  the  differences  in  the  teeth  of  files,  there 
are  differences  in  size  and  shape,  adapting  them 
to  different  kinds  of  work.  The  files  that  will  be 
most  useful  in  such  work  as  you  will  do  are  such 
as  are  shown  in  Fig.  74,  and  are  called  taper- 


138 


FIRST  LESSONS  IN  METAL- WORKING. 


flat."  Their  cross-section  is  rectangular;  but  they 
are  not  of  equal  section  tbrougliout,  being  tapered 
both  in  breadth  and  thickness,  and  swelled  or 
bellied"  in  the  middle.  They  vary  in  length 
from  about  4  to  24  inclies,  and  will  be  most  con- 
venient for  your  work  if  about  10  to  12  inches 
long.  With  such  a  file  you  may  now  produce  a 
smooth,  plane  surface  on  the  cast-iron  block  of 
Exercise  37.  Use  a  somewhat  coarse  file  for  the 
first  steps  of  the  work,  and  afterwards,  for  finish- 
ing, a  finer  one.  Put  the  block  in  the  vise  with 
Exercise  42.  chipped  facc  about  \"  to  I''  above 
FUinga  the  Jaws.  For  work  such  as  this  the 
plane  surface,  ^^j^^  ought  to  be  at  such  a  height  as  to 
brino;  the  work  about  to  the  level  of  the  elbow. 
For  much  larger  work  it  should  be  lower,  to 
enable  you  to  throw  the  weight  of  the  body  on 
the  file,  and  for  very  small  and  fine  work,  higher, 
to  allow  you  to  see  it  more  distinctly.  Spread 
your  legs  apart  a  little,  clasp  the  file  in  the  right 
hand,  the  fingers  being  below  and  the  thumb  on 
top,  hold  the  point  of  the  file  between  the  thumb 
and  fingers  of  the  left  hand  to  press  it  down,  and 
push  the  tool  forward.  The  length  of  the  file 
should  point  not  straight  forward,  but  a  little 
towards  the  left,  and  the  movement  of  the  hand 
should  also  be  a  little  towards  the  left  as  well  as 
forward,  but  with  occasionally  a  few  strokes  to- 
wards the  right  to  prevent  the  teeth  from  follow- 


FILING, 


139 


ing  their  old  tracks  and  scratching  the  work  too 
deeply. 

The  principal  difficulty  in  using  the  file  is  to 
move  it  forward  without  giving  it  a  rocking  mo- 
tion— a  difficulty  about  the  same  as  that  encoun- 
tered in  using  the  jack-plane  (Wood-working,  p. 
(34).  If  you  lower  the  point  as  you  push  it  for- 
ward and  raise  it  as  you  draw  it  back,  as  you  will 
find  yourself  inclined  to  do,  you  will  cut  off  the 
front  and  rear  edges  of  the  work  more  than  the 
middle,  and  will  produce  a  curved  surface ;  but  if 
you  keep  the  file  quite  level  and  move  it  with  long 
strokes,  you  will  cut  equally  across  the  whole 
breadth,  and  produce  a  plane  surface.  Test  your 
work  with  respect  to  this  point  from  time  to  time 
as  you  proceed,  by  applying  a  "straight-edge." 
Tt  will  not  be  enough  to  apply  the  straight-edge 
in  one  direction,  parallel,  for  instance,  to  a  b,  Fig. 
77,  because  it  is  possible  for  the  lines  a  b,  c  d 

and  E  F  to  be  all  straight,    ^  5  

and  yet  the  surface  not  to 
be  plane  but  to  have  two 

opposite  corners,  as  a  and   c  d 
F,  higher  than  the  others. 
Neither  is  it  sufficient  to 

apply  the    straight-edge    ^  ^  ^ 

parallel    to   one    of    the  Fig.  77. 

diagonals;  but  if  it  is  applied  parallel  to  both 
diagonals  and  both  edges,  it  will  be  impossible  for 


140 


FIRST  LESSONS  IN  METAL- WORKING, 


it  to  toucli  alono;  all  these  lines  if  the  surface  is 
warped,  or  "in  winding."  Trying  the  surface, 
therefore,  in  all  directions,  and  I'emoving  the  high 
parts  carefully  with  the  round  or  bellied  part  of 
the  file,  and  with  lighter  and  lighter  strokes  as 
the  piece  becomes  more  and  more  nearly  true,  you 
will  finish  it  at  length  to  a  true  plane,  or  as  nearly 
so  as  it  is  practicable  to  make  it  with  the  file. 

As  another  exercise,  involving  gi'eacer  diflicul- 
ties  than  the  last,  you  may  now  finish  up  the 
hexagonal  prism  of  brass  made  in  Exercise  39. 

You  will  make,  1st,  one  of  the  hex- 
agonal bases  plane  and  perpendicular  to 
the  faces  of  the  prism  ;  2d,  the  other 
base  plane,  parallel  to  the  first,  and  at 
the  proper  distance  (2'')  from  it ;  3d,  one  of  the 
rectangular  faces  plane,  of  the  proper  width,  and 
perpendicular  to  the  bases;  4th,  two  adjacent 
faces  plane,  of  proper  width, 
perpendicular  to  the  bases,  and 
inclined  at  the  proper  angle 
(120^)  to  the  first  face;  5th, the 
last  three  faces  plane,  parallel  to 
the  first  three,  and  of  the  proper 
width. 

First  try  with  a  square,  as  in 
Fig.  78,  whether  one  of  the  bases 
is  perpendicular  to  the  six  faces. 
If  either  of  the  angles  is  acute,  the  base  is  to  be 


Exercise  43. 
Filing  up  a 
hexagonal 
prism. 


-FILING. 


141 


filed  off  at  this  place.  Holding  the  block  in  the 
vise,  file  the  base  true  as  in  the  last  exercise,  using 
a  coarse  file  first  and  afterwards  a  new  and  fine  one 
and  trying  the  surface  in  all  directions  with  a  short 
thin-edged  straight-edge  while  working,  and  with- 
out removing  the  piece  from  the  vise  for  the  pur- 
pose. 

When  this  surface  will  bear  every  test,  proceed 
to  the  next — the  opposite  base.  Since  this  is  to 
be  made  parallel  to  the  first,  whether  that  is  per. 
pendicular  to  the  faces  or  not,  it  is  to  be  tested, 
not  with  the  square,  but  with  the  straight-edge 
and  the  calipers.  Fig.  79.  They  are  opened  to  the 
width  of  exactly  2^^,  and  are 
to  be  applied  to  the  work 
repeatedly  as  the  second  sur- 
face approaches  completion, 
to  prevent  the  cutting  away 
of  more  than  the  proper 
amount  of  metal.  Before 
the  piece  is  ready,  however, 
for  the  use  of  this  tool,  it  is 
to  be  first  marked  to  the 
proper  height,  and  then  cut 
down  close  to  the  mark.  The  rectangular  faces 
being  too  rough  to  show  a  fine  mark,  may  be  first 
filed  smooth  enough  for  this  purpose.  To  avoid 
injuring  the  finished  base  in  this  operation,  use 
the  false  jaws  of  lead  or  brass.    Be  careful,  in  this 


142         FIRST  LESSONS  IN  METAL- WORKING. 


first  filing  of  these  faces,  to  take  off  no  more  than 
Just  enough  to  enable  them  to  show  a  fine  mark. 
Chalk  the  sides.  Set  the  piece  up  on  its  finished 
base,  on  a  "surface-plate."  This  is  a  square  plate 
or  block  of  hard  cast-iron,  which  has  been  finished 
as  nearly  as  possible  to  a  true  plane  surface,  and 
serves  as  a  standard  of  comparison  for  other  sur- 
faces which  are  to  be  made  plane.  The  prism 
being  set  on  this,  is  held  firmly  with  one  hand, 
while  the  "  scriber  block"  s.  Fig.  80,  is  held  on  the 
plate  with  the  other  hand,  and  the  "scriber- 
point,"  p,  after  being  set  to  the  exact  height  of  2'^ 
above  the  base  by  the  screw  v,  is  carried  carefully 
round  all  the  faces  of  the  prism,  making  a  fine 
mark.  Then,  holding  the  prism  in  the  vise,  cham- 
fer the  upper  base  down  to  this  mark,  and  cut  it 
down,  first  with  a  coarse  and  afterwards  with  a 
fine  file.  As  you  approach  the  mark,  work  more 
and  more  carefully.  When  very  near  the  mark 
use  the  calipers  frequently  at  all  points  of  the  two 
bases,  till  the  prism  measures  exactly  Exercise  44. 
the  right  height  at  all  points.  Be  Use  of  scriber 
careful  not  to  force  the  calipers,  nor  calipers, 
yet  to  make  them  go  on  too  loosely.  They  must 
just  touch  closely,  and  so  that  no  rattle  is  possible. 
If  the  Joint  is  tight,  as  it  ought  to  be,  the  width 
between  the  points  will  not  be  altered  by  sliding 
them  on  and  off  repeatedly,  unless  considerable 
force  is  used.    Furthermore,  they  must  be  held  in 


FILING, 


143 


the  proper  position  while  being  nsea.  If  one 
point  is  farther  advanced  on  the  surface  than  the 
other,  as  at  a,  Fig.  81,  you  may  work  the  piece 


Fig.  80. 

too  short;  and  you  will  do  the  same  if  one  is  in- 
clined to  the  right  of  the  other,  as  at  b.  In  short, 
the  line  joining  the  two  points  must  be  exactly 
perpendicular  to  the  two  surfaces,  and  when  it  is 


144 


FIRST  LESSONS  IN  METAL- WORKING. 


lield  thus,  the  two  points  must  just  touch  both 
surfaces.    Finally,  the  calipers  must  be  handled 


Fig.  81,  a. 

carefully,  being  laid  down  on  the  bench  gently, 
so  as  not  to  alter  their  adjustment,  and  must  be 


Fig.  81,  b. 

occasionally  tested  by  comparison  with  the  rule, 
or  with  a  block  already  finished  to  the  right  size. 
"When  the  distance  between  the  two  bases  is 


FILING. 


145 


everywhere  exactly  2'',  the  second  surface  is  parallel 
to  tne  first,  and  is  plane,  provided  the  first  is  so. 
You  should  not  neglect,  however,  to  apply  the 
straiorht-edo-e  in  all  directions  on  the  second  sur- 
face,  as  an  additional  test.  This  may  be  done 
without  removing  the  piece  from  the  vise,  if  you 
stoop  down,  so  as  to  see  under  the  edge. 

Protecting  the  finished  bases  by  false  jaws,  file 
up  one  of  the  faces.  The  process  is  essentially 
the  same  as  before,  but  even  more  care  is  neces- 
sary, to  avoid  filing  away  too  much.  As  all  the 
lines  previously  drawn  on  the  bases  have  been 
filed  away,  it  will  be  well  to  draw  them  again, 
but  very  lightly,  with  sharp-pointed  compasses 
and  a  marking-awl,  and  then  take  care  not  to 
work  beyond  them.  When  one  of  the  rectangu- 
lar faces  has  been  finished,  the  template  should  be 
used,  as  well  as  the  straight-edge,  in  filing  the 
others,  care  being  taken,  however,  to  test  the  cor- 
rectness of  the  template,  and  to  apply  it  properly, 
as  explained  in  Exercise  39. 

If  properly  finished,  the  prism  will  stand  the 
following  tests : 

P.  All  the  surfaces,  as  tested  with  the  straight- 
edge, will  be  true  planes. 

2°.  Each  pair  of  opposite  surfaces  will  be  par- 
allel, as  shown  by  the  calipers. 

3°.  All  the  faces  will  be  perpendicular  to  the 
bases,  as  shown  by  the  square. 


146 


FIRST  LESSONS  IN  METAL-WORKING. 


4°.  All  the  angles  will  be  true,  as  measured  by 
the  template. 

5"".  All  the  faces  will  be  of  equal  width. 

6°.  All  the  edges  will  be  straight  and  sharp, 
and  all  the  surfaces  smooth,  and  free  from  coarse 
scratches,  showing  only  the  fine  and  regular  marks 
of  the  file. 

Other  methods  of  producing  a  finer  finish  on 
surfaces,  known  as  draw^-filing,  scraping,  grinding, 
oil-finishing  and  polishing,  will  be  explained  here- 
after. 

As  a  last  exercise  in  filing,  finish  the  slot  that 
you  began  in  Exercise  41,  making  it  84  mm.  X  12 
mm.  The  surface  being  in  this  case  narrow,  con- 
siderable care  will  be  needed  to  avoid  cutting  ofip 
one  edge  more  than  the  other,  and  you  must  look 
frequently  at  the  back  of  the  work  to  see  that  you 
are  not  passing  the  mark.  You  will  lessen  the 
trouble  of  this  part  of  the  work^  if,  as  in  working 
to  a  mark  in  general,  you  first  cut,  on  each  side, 
a  chamfer  down  to  the  mark,  which  will  then 
serve  as  a  guide.  The  ends  of  the  slot,  which 
were  left  round  by  the  drill,  are  to  be  filed  square 
with  the  edge  of  the  file.  After  the  ends  are 
finished,  if  any  more  work  is  to  be  done  on  the 
sides,  for  the  purpose  of  finishing  up  the  corners 
sharp  and  clean,  the  "safe  edge"  of  the  file  which 
has  no  teeth,  should  be  used  in  the  corner,  so  as 
to  avoid  injuring  the  finished  end.    If  the  file  hao 


FiLim. 


BO  safe  edge^  you  can  make  one  by  grinding  off 
the  teetli  on  one  edge.  This  will  be  even  better 
than  the  safe  edge  made  by  the  manufacturer,  as 
the  teeth  on  the  face  will  come  up  more  sharply 
to  the  edge,  and  will  finish  the  corners  better. 
The  tests  of  the  work  are  obvious.  The  sides  and 
ends  must  be  straight  and  plane,  and  perpendicu- 
lar to  the  face  of  the  plate  and  to  each  other,  and 
the  slot  must  be  exactly  true  to  the  proposed 
dimensions,  84  mm.  X  12  mm. 


148         FIRST  LESSONS  IN  METAL^WOEKING. 


LESSON  XXIL 

SOLDERING.      BUNSEN  BURISTER. 

We  have  now  learned  how  to  give  approxi- 
mately any  desired  form  to  wrought-iron  or  steel 
by  forging  and  welding,  and  to  cast-iron,  steel, 
brass,  zinc,  and  other  easily  fusible  metals  by 
founding.  When  the  approximate  form  has  been 
given,  we  have  seen  how  to  produce  small  changes 
by  chipping  and  filing.  We  have  now  to  learn 
another  method  of  building  up  complex  forms  by 
uniting  simpler  pieces,  which  partakes  in  part  of 
the  nature  of  welding,  and  in  part  of  that  of  cast- 

Soldering  is  uniting  two  pieces  of  metal  by 
means  of  another  metal.  This  other  metal  may 
be,  first,  one  which  melts  at  a  lower  temperature, 
and  which  adheres  closely  to  the  two  pieces  or 
partially  combines  with  them  and  thus  Joins  them 
together ;  or,  secondly,  it  may  be  the  same  metal 
as  that  of  w^hich  the  two  pieces  are  composed.  In 
the  first  case  the  operation  is  very  much  like  that 
of  gluing.    It  is  called    soft  soldering"  when  the 


SOLDERING.    BVNSEN  BURNER. 


149 


solder  is  an  alloy  of  tin  and  lead,  sometimes  with 
the  addition  of  bismutli  to  make  it  more  fusible ; 
anc;  hard  soldering''  when  a  less  fusible  material 
is  used,  as  gold,  silver,  copper,  or  an  alloy  of  tin 
lead,  and  zinc,  called  spelter  solder.  In  the  second 
case,  when  the  pieces  are  joined  by  a  portion  of 
the  same  metal,  the  operation  is  moi'e  analogous 
to  welding,  and  is  called  "burning"  or  "brazing." 
A  few  examples  will  make  clear  the  nature  of  the 
operations  and  the  mode  of  proceeding. 

For  a  first  exercise.  Join  with  soft  solder  two 
pieces  of  brass  in  the  manner  shown  in  Fig,  82. 
File  the  edge  of  the 
piece  A  straight  and 
square.  Scrape  or  file 
the  surface  of  b  clean, 
\vhere  a  is  to  join  it. 
The  two  are  now  ready 
for  the  solder. 

As  in  welding,  so  in 
soldering,  it  is  necessary  (Full  size.) 

that  the  two  surfaces  should  be  clean  and  free 
from  oxide.  A  flux  is  therefore  used  as  in  weld- 
ing, to  carry  off  the  oxide  that  will  be  formed  on 
the  surface  when  heated,  as  well  as  any  dirt  that 
may  be  there.  Various  fluxes  are  used  for  differ- 
ent kinds  of  work,  as  borax,  sal  ammoniac,  resin 
and  muriate  of  zinc.  For  this  exercise  we  will  use 
the  last.    It  is  prepared  by  dissolving  scraps  of 


150 


FIRST  LESSONS  IN  METAL-  WORKING. 


zinc  in  dilute  hydrochloric  acid.  A  small  wide- 
necked  bottle  of  this  solution  is  kept  on  the  bench 
ready  for  use.  It  should  have  a  piece  of  iron  wire 
thrust  through  the  cork  and  dipping  down  into 
the  fluid.  With  this  a  drop  or  two  of  the  fluid  can 
Exercise  45.  be  applied  to  the  surface  of  a  piece  of 
Soldering  metal  as  needed.  Or,  a  stouter  piece  of 
brass  with  ^^'^^^  niay  be  fitted  with  a  wooden  handle 
soft  solder.  and  uscd  for  this  purpose,  as  well  as 
for  "  tinning"  small  surfaces,  such  as  those  of  this 
exercise.  For  the  latter  purpose  the  wire  must  it- 
self be  tinned  at  the  end.  To  tin  the  wire,  dip  it 
into  the  solution,  then  hold  it  in  the  flame  of  the 
Bunsen  burner,  the  outer  tube  of  the  burner  being 
turned  so  as  to  admit  plenty  of  air,  giving  a  blue 
flame.  If  the  air  supply  is  insufiicient,  the  flame 
will  be  yellow  and  smoky,  and  not  so  hot.  Rub 
the  end  of  the  wire  with  the  solder-stick,  using 
the  "  tin-solder"  compound  of  3  parts  of  tin  to  2 
of  lead,  or  2  of  tin  to  1  of  lead.  The  solder  will 
adhere  to  the  surface  wherever  it  is  clean.  If 
there  is  any  spot  where  it  does  not  adhere,  it  must 
be  cleaned  with  the  file  oi'  a  piece  of  sandstone, 
and  the  operation  repeated.  With  the  tinned  wii'e 
we  can  now  tin  the  surfaces  of  the  brass.  Hold 
the  piece  a  in  the  flame  with  pliers.  Apply  a 
drop  of  the  flux  to  the  edge  with  the  tinned  wire, 
and  as  it  boils  off  rub  the  wii'e  to  and  fro  along 
the  edge  till  the  latter  is  covered  with  a  bright 


SOLDERING.    BVNSEN  BURNER.  151 

clean  layer  of  the  solder;  or,  toiicli  it  witli  the  sol- 
der stick  till  a  drop  of  the  solder  adheres,  and 
then  spread  it  along  the  edge  with  the  wire.  "With- 


FiG.  83. 


draw  it  from  the  flame  and  let  it  cool.  Tin  in  the 
same  way  the  portion  of  b  on  which  a  will  rest 
The  two  surfaces  will  now  unite,  if  held  together 


152         FIRST  LESSONS  IN  METAL-  WORKING. 


while  the  solder  is  melted.  They  may  be  held 
together  in  various  ways. 

1.  The  piece  b  may  be  laid  on  a  retort-stand, 
Fig.  83,  and  the  pi'ece  a  set  up  on  it  at  the  proper 
place.  The  flame  being  then  applied  below  b, 
the  solder  will  melt,  and  then,  the  flame  being  re- 
moved, the  piece  will  cool.  As  the  two  surfaces 
of  the  solder  are  somewhat  round,  it  is  difl&cult  to 

make  the  thin  piece  a  stand 
upright.  It  may  be  held 
down  during  the  melting 
with  a  pointed  wire,  or  still 
better  by  means  of  a  wire 
spring  of  hard  brass,  as  in  Fig.  84.  In  either  case 
it  will  be  best  to  file  the  two  round  surfaces  of  the 
solder  flat  before  putting  them  together.  Or, 

2.  The  pieces  may  be  held,  one  in  each  hand, 
with  a  pair  of  pliers,  [and  pressed  lightly  to- 
gether in  the  flame  till  the  solder  melts,  and  then 
removed  to  cool.  Or, 

3.  Clamped  together  by  the  spring  as  in  case  1, 
they  may  be  held  in  the  flame  with  a  pair  of 
pliers,  and  soldered  and  cooled  as  before. 

With  such  light  pieces  as  these  the  last  method 
will  probably  be  found  the  most  convenient.  If 
the  piece  a  were  considerably  heavier,  and  broader 
at  the  base,  its  own  weight  would  keep  it  in  posi- 
tion, and  no  special  device  would  be  needed  for 
holding  it. 


SOLDERING,  BUN  SEN  BURNER. 


153 


The  two  pieces  of  this  exercise  may  be  soldered 
without  previous  tinning,  if  the  surfaces  are  thor- 
oughly clean.  Hold  the  pieces  together  with  a 
spring,  as  before.  Taking  b  in  the  pliers  with 
the  left  hand,  put  a  drop  or  two  of  flux,  and  a  few 
small  chips  of  solder  cut  off  with  a  knife,  in  each 
of  the  angles.  Heat  the  pieces  in  the  flame.  First 
the  flux  will  flow  into  the  joint  and  afterwards 
the  solder.  If  the  solder  does  not  spread  along 
the  whole  length  of  the  joint,  draw  it  along  with 
the  end  of  the  fine  wire  which  is  in  the  bottle. 
Cool  as  before. 

In  whichever  way  the  pieces  are  prepared  and 
heated,  the  principal  points  to  be  heeded  are : 

1.  To  have  the  surfaces  quite  clean. 

2.  Not  to  allow  the  pieces  to  be  displaced  by 
the  boiling  of  the  flux  or  the  melting  of  the  solder. 

3.  Not  to  hold  the  pieces  in  the  flame  longer 
than  is  necessary  to  melt  the  solder,  as  overheat- 
ing burns  the  solder  and  weakens  the  joint. 

4.  Not  to  disturb  the  pieces  till  the  solder  has 
set,"  or  hardened.    The  moment  of  setting  can 

generally  be  observed  by  watching  closely.  At 
this  moment  the  bright  surface  of  the  solder  be- 
comes dulled  by  the  formation  of  a  multitude  of 
minute  wrinkles  as  the  metal  contracts.  The 
cooling  may  be  hastened,  in  the  case  of  very  light 
pieces,  by  blowing,  and  in  that  of  heavier  pieces 
by  applying  a  few  drops  of  water. 


154 


FIRST  LESSONS  IN  METAL- WORKING, 


5.  Not  to  use  too  much  solder.  Besides  beino; 
wasteful,  this  fills  up  the  angle,  and  the  excess 
will  have  to  be  filed  away  to  make  a  neat  Job. 

Where  gas  cannot  be  used,  the  exercises  of  this 
lesson  can  be  performed  with  a  blow-]3ipe  (as  in 
Lesson  XXIV)  or  with  a  blast-lamp,  Fig.  85. 
This  is  an  alcohol  lamp,  a,  which  burns  under  a 
vessel  of  alcohol,  b.    The  alcohol  in  b  boiling, 


Fig.  85. 

drives  off  first  the  air  and  then  alcohol  vapor 
through  the  tube  c,  thus  blowing  a  strong  blast 
through  the  flame  of  the  lamp,  and  shooting  out  a 
tongue  of  hot  flame  which  can  be  directed  on  the 
work.  If  the  lamp  alone  is  used,  and  the  blast  is 
produced  by  blowing  w4th  the  mouth  through  a 
bent  tube,  the  instrument  becomes  an  ordinary 
blow-pipe. 


SOLDEBING.    BUNSEN  BURNEB, 


155 


It  is  obvious  that  such  a  joint  as  that  in  the 
last  exercise  cannot  have  any  very  great  strength. 
It  will  nevertheless  often  be  useful  w^hen,  as  in 
experimental  work  in  the  physical  laboratory,  it 
is  desired  to  put  two  pieces  together  quickly,  and 
strength  is  not  important. 

Let  us  now  look  a  little  more  closely  into  the 
strength  of  a  soldered  joint.    Join  two  pieces  of 

i   '    ■  — ' 

\      M  / 

Fig.  86.    (Full  size.) 

brass  with  a  lap-joint"  as  in  Fig.  86,  cleaning 
and  tinning  the  surfaces,  and  holding  them  to- 
gether in  the  flame  with  a  pair  of  pliers.  Put  the 
jointed  strip  into  the  small  testing-machine  (Wood- 
working, Fig.   8,  p.  19),  and  pull  till   Exercise  46. 

the  joint  breaks.    Record  the  force  Testing  a  soi- 
used.    Put  one  of  the  pieces  into  the 
machine  and  break  it,  and  record  the  force  used. 
Find, 

1.  How  many  times  stronger  the  brass  is  than 
the  soldered  joint. 

2.  How  many  times  stronger  the  brass  is  than 
a  soldered  joint  of  the  same  area  as  the  cross-sec^ 
tion  of  the  brass  ;  and  thence, 


156         FIRST  LESSONS  IN  METAL-  WORKING, 

3.  How  large  the  Joint  should  be  to  be  just  as 
strong  as  the  brass. 

Then  make  another  joint  of  the  same  kind, 
with  a  lap  just  sufficient  to  make  the  joint  as 
strong  as  the  metal.  Test  the  metal  and  the  joint 
in  the  machine  and  record  the  result.  You  will 
know  henceforth  how  large  a  joint  surface  to  al- 
low, with  this  kind  of  solder  and  this  kind  of 
brass,  if  you  wish  the  joint  to  be  as  strong  as  the 
metal.  Strono-er  than  the  metal  it  is  not  worth 
while  to  make  it. 


SOLDEBim.    THE  SOLDERING  IRON.  157 


LESSON  XXIII.  : 

SOLDERIlSrG.      THE  SOLDERING-IROiq'. 

When  the  pieces  are  large,  it  is  convenient  and 
usual  to  heat  only  the  part  which  is  to  be  soldered, 
leaving  the  rest  cool.  This  is  done  with  the"  bit" 
or  "soldering-iron." 

The  iron  is  first  to  be  tinned.  Heat  it  to  a  dull 
red  on  a  charcoal  fire,  or  over  a  large  Bunsen 
burner.  File  the  sides  bright,  quickly.  Exercise  47. 
Rub  it  on  a  piece  of  board  sprinkled  Tinning  a  soi- 
with  powdered  sal-ammoniac  or  resin,  ^^^^^-^'^on. 
and  then  on  a  plate  of  copper  on  which  are  some 
chips  of  solder.  Wipe  it  clean  with  a  rag.  If 
you  have  allowed  it  to  fall  below  the  temperature 
at  which  solder  melts,  the  operation  will  fail,  and 
reheating  will  be  necessary.  If  afterwards,  in 
using  the  soldering-iron,  you  overheat  it,  the  tin 
will  burn  off,  and  you  will  have  to  tin  it  again. 

We  will  now  make  a  Joint  somewhat  like  that 
in  Exercise  45,  but  longer  and  stronger,  and  be- 
tween two  sheets  of  tin  (that  is,  tinned  iron),  ar- 
ranged as  in  the  isometric  sketch,  Fig.  87.  Mois- 


158 


FIRST  LESSONS  IN  METAL-  WORKING. 


ten  the  angle  c  between  tlie  two  pieces  with  flux, 
or  sprinkle  it  with  powdered  resin.  Scatter  along 
it  small  chips  of  solder.  Hold  the  piece  a  down 
firmly  at  one  end  with  the  end  of  a  file,  or  any 
pointed  tool,  and  melt  a  drop  of  solder  in  the 
angle.  This  will  fasten  or  tack"  the  piece  at 
one  end.    Tack  it  in  the  same  way  at  the  other 


FiG.  87. 


end.  This  will  hold  it  in  place  while  you  finish 
the  Job.  Hold  the  piece  level,  or  inclined  in  such 
a  way  that  the  solder  shall  run  into 
the  Joint.  Draw  the  bit  slowly  along 
the  angle,  melting  the  solder  and  caus- 
ing it  to  run  into  the  Joint.  If  any  part 
is  missed,  go  over  it  again  in  the  same  way. 

The  two  sheets  of  metal  in  the  last  exercise  are 
in  planes  perpendicular  to  each  other.  In  this 
case,  when  the  Joint  is  at  the  edges  of  both  pieces, 


Exercise  48. 
Soldering 
with  the  sol- 
dering-iron. 
Tin  on  tin. 


SOLDEBINO.    THE  SOLDEBING  IRON.  159 


it  may  be  made  as  in  Fig.  88,  a  or  b.  The  joint 
A  would  be  tacked  and  soldered  as  in  the  exercise 
Just  finished.  In  b  the  lower  piece  should  be 
closed  tightly  on  the  nppei'  with  the  hammer,  and 
then  soldered  along  both  the 
exterior  and  the  interior  an- 
gle.   The  manner  of  bending  a 

the  sheets  for  this  exercise   J 

and  the  last  will  be  explained  '  '  ^ 

in  connection  with  the  next.  ^ 

When  the  two  sheets  are 
to  be  in  the  same  plane,  there  b 
are  several  ways  in  which  — 
they  may  be  joined.    These  ' 
are  shown  in  Fig.  89.  ^^^g-  s^-  (FuH  size.) 

The  joint  a  is  called  the  lap-joint.  It  needs 
but  to  be  tacked  at  two  or  three  points,  as  in  Ex- 
ercise 48,  and  soldered  as  there  described. 

B  is  a  cramp-joint."  The  edge  of  the  left- 
hand  piece  is  thinned  almost  to  a  knife-edge  by 
hammering  on  a  small  anvil.  The  edge  of  the 
other  is  nicked  obliquely  with  the  shears,  and  the 
pieces  between  the  cuts  are  turned  alternately  up 
and  down.  The  thinned  piece  is  pushed  into  the 
V-shaped  space  thus  made,  and  the  "  cramps"  are 
hammered  down  on  it.  It  is  then  tacked  and 
soldered. 

The  edges  of  the  two  pieces  in  c,  as  well  as  in 
B,  Fig.  88,  and  a.  Figs.  87  and  88  are  prepared 


160         FIRST  LESSONS  IN  METAL-  WORKING. 

on  a  tool  called  the  "hatchet-stake,"  Fig.  90, 
which  is  set  in  a  hole  in  the  top  of  the  work- 
bench. The  sheet  is  laid  on  the  edge  ab  at  a 
proper  distance  from  the  edge  of  the  sheet,  and 
turned  over  by  blows  of  a  flat  mallet,  the  edge 


Fig.  89.    (Scale  i.) 


being  either  turned  up  at  right  angles  to  the 
sheet,  or  doubled  over  on  it,  according  to  the 
kind  of  Joint  proposed. 

As  an  exercise  in  this  kind  of  soldering,  and 
one  in  which  a  water-tight  joint  is  required,  make 
a  cubical  box  of  tin  or  sheet  brass,  whose  edges 


SOLDERING,    THE  SOLDERING  IRON 


161 


shall  have  the  length  of  one- decimeter  exactly, 
inside.    Such  a  vessel  will  be  a  "  liter"  measure. 

The  bottom  must  be  cut  to  the  form  and  dimen- 
sions shown  in  Fig.  91,  a,  and  must  be  bent  up- 
ward, at  right-angles,  along  the  dotted  Exercise  48. 
lines.    The  sides  are  shown  at  b,  and  a  cubical 
are  to  be  bent  at  right  angles  along 
ad^  dc^  and  ch^  and  doubled  along  ah.    The  notches 


Scale,  a 


Fig.  90.    (Scale  J.) 

at  the  corners  show  where  pieces  must  be  cut  out 
to  let  the  upturned  edges  lie  flat.  The  dimensions 
in  the  figure  are  those  that  all  the  pieces  should 
have  if  the  material  had  no  thickness.  Owing 
to  the  thickness  of  the  metal  these  must  be 
slightly  altered,  and  the  amount  of  the  alteration 
will  depend  on  the  thickness.    If  the  bottom  is 


162 


FIRST  LESSONS  IN  METAL- WORKING. 


put  on  outside  of  the  other  pieces,  it  will  be  nec. 
essary  to  make  its  inside  dimensions  larger  by 
twice  the  thickness  of  the  metal.    Furthermore,  as 


-10  cm 


12cm.-=  


3 


1 


[<  ^lOcm,  

Fig.  91. 


two  opposite  sides  of  the  vessel  are  turned  over  the 
other  two,  the)'  also  must  be  made  wider  by  twice 
the  thickness,  and  all  the  sides  must  be  higher  by 


SOLDEBING.    THE  SOLDERINO  IRON. 


163 


once  the  tliickness.    It  \\  ill  be  well  to  cut  out  tlie 
pieces  in  card-board  and  put  tliem  together,  to 
assure  yourself  that  you  can  cut  them  correctly ; 
make  the  proper  allowance  for  thickness,  and  put 
them  together  properly.    Then  mark   out  the 
pieces  with  a  "  sci'atch-aw]/'  Fig.  92,  and  cut  them 
out  with  the  shears.    Bend  the  edges  of 
the  bottom  upwards,  the  upper  edges  of 
the  sides  outwards,  and  the  other  edges 
inwards,  over  the  hatchet-stake,  being  care- 
ful to  keep  them  quite  straight,  and  not 
to  bruise  the  sheets.    Set  the  five  pieces 
together  to  assure  yourself  that  they  fit 
properly.    You  will  now  discover  that  the 
overturned  edges  of  the  larger  side-pieces, 
overlapping  the  smaller  side-pieces,  pre- 
vent the  bottom  from  going  on,  and  four 
small  square  pieces  have  to  be  cut  out  from 
the  bottom  of   these.     This  cut  is  not 
shown  in  the  sketch,  and  you  must  deter- 
mine for  yourself  its  proper  size  and  shape.  Cut 
out  these  pieces  with  small  shears,  being  careful 
not  to  make  the  cuts  too  large. 

Now  lay  one  of  the  larger  sides  on  your  bench, 
and  join  the  two  narrower  sides  to  it  as  in  Exer- 
cise 48,  Fig.  87,  being  careful,  in  soldering,  not 
to  miss  any  portion  of  the  joint.  Lay  the  other 
lai'ge  side  on  the  bench,  and  repeat  the  same 
operation.    The  four  sides  are  now  fastened  to- 


164 


FIBST  LESSONS  IN  METAL-  WORKING. 


gether,  and  ready  for  the  bottom.  Set  the  bottom 
in  place,  and  solder  it  in  the  same  manner. 

When  the  vessel  is  finished,  all  the  angles 
should  be  perfectly  square,  all  the  faces  flat,  and 
all  the  Joints  perfectly  water-tight  and  perfectly 
smooth  inside  and  outside,  showing  no  places 
without  solder  and  no  lumps  of  unnecessary  solder, 
and  the  internal  dimensions  should  be  exactly  10 
centimeters  each  way. 


SOLDERING.    BLO  WFIPR 


166 


LESSON  XXIV. 


SOLDEEING.  BLOW-PIPE. 


When  a  very  small  piece  is  to  be  soldered  to  a 
much  larger  one,  it  is  often  convenient  to  use  tlie 
blow-pipe  instead  of  either  the  Bunsen  burner  or 
the  soldering-iron,  as  with  this  an  intense  heat  can 
be  applied  on  a  very  small  area.  As  an  example 
of  such  a  joint  we  will  solder  an  elec-  Exercise  49. 
trical  "binding-post/'  a,  Fig.  93,  to  a  Use  of  the 
brass  plate  b.  Take  a  piece  of  sheet  ^i^^-p^p^' 
brass  about  5*^™  long,  3'™  wide,  and  3™"  thick.  Make 
the  end  of  the  post  flat,  and  clean  with  the  file. 
Scrape  or  file  the  portion  of  the  plate  at  which 
the  post  is  to  be  attached.  Lay  the  plate  on  any 
convenient  support,  and  set  the  post  on  it. 
Moisten  the  angle  all  round  with  a  drop  or  two 
of  the  zinc  solution,  and  lay  a  few  granules  of 
solder  there.  Set  the  Bunsen  burner  by  the  side 
of  the  work,  with  the  bottom  of  the  flame  about 
on  a  level  with  the  plate.  Turn  the  outer  tube 
of  the  burner  so  as  to  shut  off  the  supply  of  air 
at  the  bottom,  giving  a  yellow  instead  of  a  blue 


166         FIRST  LESSONS  IN  METAL  WORKING. 

flame,  and  less  heat.  Holding  the  blow-pipe  in 
the  right  hand,  with  the  tip  just  outside  the  flame, 
direct  the  current  of  air  from  the  mouth  through 
the  lower  part  of  the  flame.  This  will  produce  a 
long  slender  jet  of  blue  flame,  in  which  the  tem- 
perature is  very  high.  Direct  this  on  the  base  of 
the  post  and  the  plate  adjoining.  The  flux  will 
quickly  boil  away,  and  the  solder  will  melt  and 


rw~\ 


I 


Fig.  93.   (Full  size.) 

run  into  the  joint.  Remove  the  blow-pipe,  and  let 
the  work  cool. 

In  making  a  small  joint  in  this  way  yoa  must 
be  careful — 

1°.  Not  to  use  too  much  solder. 

2°.  Not  to  let  the  flame  play  on  parts  of  the 
metal  which  need  no  heat,  as  it  discolors  them. 

3°.  Not  to  continue  the  heat  longer  than  neces- 
sary. 


SOLDERING.  BLOW-PIPE. 


167 


4°.  Not  to  let  the  small  piece  be  displaced  by 
the  boiling  of  the  flux.  Hold  it  down  with  a  piece 
of  wire  if  necessary. 

There  is  sometimes  a  still  greater  necessity  than 
in  the  last  exercise  of  preventing  the  spread  of 
heat  to  other  parts  than  that  at  which  the  joint  is 
to  be  made.  A  good  example  of  this  is  in  the 
case  of  the  soldering  of  a  spring  a,  such  as  you 
made  in  Exercise  36,  to  the  plate  b,  Fig.  94.  If 


B 

Fig.  94.    (FuU  size.) 

the  spring  is  overheated,  its  temper  will  be 
"  drawn,"  and  the  spring  spoiled.  This  may  be 
avoided  by  "  sweating"  the  spring  on  the  plate. 
Tin  the  plate,  at  the  proper  point,  over  Exercise  50. 
the  Bunsen  flame.  Then  hold  the  Sweating  a 
.  spring  in  place  by  means  of  a  clamp  a, 
Fig.  95,  made  by  filing  or  sawing  a  slit  in  a  piece 
of  brass  or  copper.  Apply  flux  and  bits  of  solder 
along  the  edge  of  the  joint.  Hold  the  clamp,  not 
the  plate,  in  the  Bunsen  flame,  and  watch  the  solder 
closely.  The  heat  conducted  along  the  clamp  will 
reach  the  plate  and  melt  the  solder.  As  soon  as 
this  happens,  remove  the  work  from  the  flame, 
and  cool  it  olf  before  there  is  time  for  the  spring 
to  be  heated. 


168 


FIKST  LESSONS  IN  METAL-WORKING. 


The  exercises  45  to  50  illustrate  the  principal 
raetliods  of  uniting  small  pieces  by  means  of  soft 
solder,  or  such  as  melts  at  temperatures  below 
about  450°  F.  Joints  with  such  solder  are,  as  you 
have  found,  not  very  strong,  and  when  great 
strength  is  important,  or  when  the  joint  may  be 
exposed  to  much  heat  when  it  is  used,  a  hard  sol- 
der must  be  employed.  Hard  solders,  instead  of 
being  made  of  lead  and  tin,  are  commonly  made 


Fig.  95.    (Full  size.) 


of  copper  and  zinc,  or  of  copper  and  silver,  called 
silver  solder.  They  require  a  higher  temperature 
to  fuse  them,  and  the  management  of  them,  which 
is  somewhat  more  difficult  than  that  of  the  soft 
solders,  may  be  deferred  to  a  later  stage  in  your 
study,  along  with  brazing  and  burning. 


ALPHABETICAL  INDEX. 


Bending,  13. 
Blast-lamp,  154. 
Blow-pipe,  165. 
Bunsen  burner,  148. 
Calipers,  144. 
Cape-chisel,  114. 
Casting,  70. 
Chipping,  114. 
Cold  chisel,  making  a,  100. 
Cold-chisel,  angle  of,  104. 
Cross  cut  Chisel  114. 
Countersinking,  21. 
Cramp- joint,  159. 
Drawing  and  Pointing,  9. 
Drill,  making  a,  108. 
Drilling,  120. 

Drilling-machine,  Hand,  129. 
Eye,  making  an,  13. 
Files,  care  of,  l:)5. 
Files,  varieties  of,  133. 
File-brush,  136. 
Filing,  132. 

Filing  a  Plane  Surface,  139. 

Fire,  care  of.  7. 

Flask  (mouldiug),  66. 

Flattening,  15. 

Flatter,  50. 

Fuller,  47. 

Hack-saw,  127. 

Hardee,  5. 

Hatchet-stake,  161. 

Helper,  45. 

Hot  Chisel,  53. 

Iron,  case-hardened,  112. 

Iron,  cast,  manufacture  of,  61. 

Iron,  cast,  varieties  of,  63. 


Iron,  cast  and  wrought,  proper- 
ties of,  4. 

Iron,  chilled.  111. 

Iron,  malleable,  113. 

Iron,  pig,  62. 

Iron,  puddling,  73. 

Iron,  refining,  73. 

Iron,  rolling,  72. 

Iron,  strength  of,  58. 

Iron,  testing,  59. 

Iron,  wrought,  manufacture  of, 
71. 

Jaws  of  Vise,  false,  137. 
Lap-joint,  155. 
Link,  making  a,  43. 
Melting,  temperatures  of,  3. 
Mouldiug,  67. 
Oil,  annealing  with,  107. 
Oil,  hardening  with,  107. 
Pattern-making,  65. 
Pointing,  9. 

Prism,  making  a  Hexagonal,  123, 

140. 
Punch,  20. 
Punch,  Centre,  20. 
Punching,  18. 
Ratchet  drill,  128. 
Scarfing,  38. 
Scarf-weld,  39. 
Scriber,  142. 
Slott,  cutting  a,  130. 
Soldered  Joints,  testing,  155. 
Soldering  with  Blow-pipe,  165. 
Soldering  with  Bunsen  burner, 

148. 

Soldering  with  soft  solder,  157. 

169 


170" 


Soldering  with  soldering-iron, 
150./,  :      <'  " 

Split  Weld;  5l;      *      \  ^\  ;  '  \  , 

Spriu-g,  making  a.  1(J6. 

Steel,  annealing,  92. 

Steel,  colors  of  heated,  94. 

Steel,  hardening,  88. 

Steel,  temper  indicated  by  colors 
of,  96. 

Steel,  temperature  indicated  by 

colors  of,  95. 
Steel,  testing,  79. 


St,ef;lrrarieties  of,  76. 
3)  eel,  welding  high-grade,  85. 
Si-eel,  welding,  on  si  eel,  81. 
Steel,  welding,   on  iron,  low- 
grade,  83. 
Sweating,  167. 
Template,  123. 
Tongue-weld,  51 
Twisting,  27. 
Upsetting,  34. 
Welding,  29. 


Date  Due 

i 

